Multidimensional Taxonomies for Research, Development, and Implementation of Electric Aircraft Ecosystem

Abstract

The electrification of aviation represents a significant technological frontier, promising substantial advancements in sustainable transportation. This paper presents a comprehensive set of taxonomies that systematically categorize and analyze the multifaceted aspects of electric aviation, with a particular focus on machine-related components and systems. It provides detailed classifications of electric aircraft propulsion systems, power management architectures, and energy storage technologies, offering insight into their design, functionality, and integration challenges. The paper explores the ecosystem of electric aviation, including key stakeholders, use cases, and enabling technologies, which are vital for coordinating machine development strategies and fostering sustainable growth. The creation of business models that cater to the dynamic nature of the industry, emphasizing the role of innovative machine designs in shaping market adoption are discussed in the paper. The study highlights the importance of electric aviation for regional development, outlining predictive models for regional market development that consider machine capabilities and infrastructure requirements.

1. Introduction

The electrification of aviation has become an increasingly important focus area for the air transport industry in recent years. With rising fossil fuel costs, growing environmental concerns, and the need for new efficiencies, electric and hybrid-electric aircraft are being seen as a potential breakthrough technology.

Aviation is responsible for 12% of global CO₂ emissions from all transport sources, compared to 74% from road transport, and commercial aviation is responsible for about 2–3% of global carbon emissions [1,2]. So, the motivation to reduce dependency on conventional jet fuel through electrification is substantial.

Electric aircraft utilize batteries and electric motors rather than internal combustion engines as their source of propulsion. This can lead to significant improvements in energy efficiency, reductions in noise and emissions, and lower operating costs compared to conventional airplanes. Additionally, the simplicity of electric motors compared to jet turbines allows for opportunities to rethink aircraft configurations for greater optimization.

For these reasons, major investments are being made into research and development of electric aircraft by industry, academia, and government.

However, widespread adoption of electric aviation still faces considerable hurdles. Battery energy densities, though improving, remain far below that of jet fuel. Electric motors do not yet match the power-to-weight ratios of jet engines. Operational factors around charging infrastructure and regulations also present challenges. As research and development accelerates, it becomes important to establish standardized frameworks for discussing and categorizing the technologies, configurations, applications, and other aspects associated with electric flight.

This paper aims to dissect the development of electric aviation (EA) through structured taxonomies, categorizing the advancements and challenges into distinct yet interconnected segments.

This study provides several novel contributions to the field of electric aviation. The key scientific advancements developed through this research include:

• The research introduces a unique, multidimensional taxonomy framework that systematically categorizes electric aircraft technologies, including propulsion systems, energy management strategies, infrastructure requirements, and regulatory factors. These taxonomies serve as a crucial tool for organizing the rapidly evolving knowledge in electric aviation, facilitating interdisciplinary communication and guiding further research.
• The study incorporates predictive models that assess the impact of electric aviation on regional transport networks. These models help to forecast infrastructure needs, stakeholder engagement, and market adoption. Such models are critical for planning the expansion of electric aviation and understanding its socio-economic and environmental impacts at the regional level.
• In addition to technological aspects, this research introduces innovative business models that consider the unique dynamics of electric aviation. These models emphasize the role of stakeholders in the value chain, operational frameworks for electric aviation companies, and the development of new market opportunities, highlighting pathways for commercialization and adoption.
• The study emphasizes the full lifecycle of electric aircraft technologies, from design and development to decommissioning and recycling. This lifecycle approach ensures that sustainability is integrated at every stage of electric aviation development, aligning with global environmental goals.

These contributions not only address the technical challenges of electric aviation but also provide insight into the broader ecosystem, ensuring the research is relevant for both academia and industry stakeholders.

The paper is structured as follows. Section 2 reviews related works in the field of electric aviation, highlighting current research trends and identifying gaps in the existing literature. Section 3 outlines the methodology employed in developing the taxonomies, explaining the rationale behind the structured approach and its scientific justification. Section 4 presents the results, including detailed taxonomies for EA classification, the EA ecosystem, main directions of scientific research in the EA domain, lifecycle considerations for EA technology, EA business models, and others. Section 5 discusses the implications of these taxonomies, comparing electric and conventional aviation applications, and exploring future research directions. Section 6 concludes the paper by summarizing the key findings and their significance for the future of EA.

2. Related Works

Electric aviation is a rapidly emerging field, garnering significant interest from both academia and the aviation industry.

The concept of electric-powered aircraft is not entirely new. However, only in recent years has the convergence of several technological advances made electric aviation appear viable for mainstream applications [3].

2.1. Electric Propulsion Systems and Technologies

The review paper [4] surveys recent advancements and future trends in sustainable aviation electrification, an approach to decarbonizing the civil aviation sector. It discusses the architectures of electrified aircraft propulsion, outlining their benefits, challenges, and current applications, delves into the technical challenges of propulsion control system design, and evaluates commonly used control methods and energy management strategies aimed at reducing fuel burn, emissions, and costs.

The paper [5] reviews advancements in electric and hybrid-electric aircraft propulsion, focusing on propulsion, actuation, and power generation as key areas for developing more electric aircraft technologies. Highlighting the environmental and operational benefits of electric systems over traditional mechanical, pneumatic, or hydraulic systems, the study points out the superior efficiency and power density of permanent magnet motors compared to switch-reluctant and induction machines.

All-electric aircraft, including vertical take-off and landing aircraft (eVTOLs) [6,7], commuter aircraft [8], rotorcraft [9,10], and general aviation airplanes, are recognized as a viable and cost-effective solution for reducing the environmental impacts associated with short-haul flights. The extent to which the global aircraft fleet can benefit from these electric aircraft significantly relies on advancements in battery pack technology [11].

The shift toward electrification in aircraft propulsion is revolutionizing traditional designs, offering new avenues for efficiency, noise reduction, and environmental sustainability. Studies indicate that evolutionary improvements in propulsion technology alone may not suffice to meet future environmental goals, necessitating radical technological changes [12]. The European Commission and NASA have set ambitious targets for emission reductions and efficiency improvements [13,14].

Electrification enables novel aircraft designs with potential performance improvements. Distributed electric propulsion enhances aerodynamic efficiency and reduces take-off and landing distances by strategically placing propulsors across the airframe [15,16,17,18,19,20,21,22,23,24,25,26]. However, these systems increase structural complexity and weight, requiring significant technological advancements to realize benefits [22,27].

2.2. Energy Management and Efficiency Strategies

Energy management strategies refer to the methods and approaches used to optimize the distribution and utilization of electrical energy in electric aircraft. These strategies involve managing power consumption during different flight phases (e.g., take-off, cruising, and landing), battery charging and discharging cycles, and ensuring efficient use of energy storage systems. The goal is to maximize flight efficiency and range while minimizing energy losses.

Various architectures have been proposed for electrified aircraft power systems, including hybrid configurations that combine conventional and electric power sources [28,29,30,31,32,33]. Key challenges in developing these systems include optimizing energy management strategies [34,35,36], ensuring reliability and safety [37,38,39,40,41,42], and addressing thermal management issues [43,44,45].

Researchers have explored different approaches for modeling and optimizing electrified aircraft power systems. These include multi-objective optimization techniques [27,28,29,30,31,32,33,34,35], convex optimization methods [36,37,38,39,40], and model predictive control strategies [41,42,43,44,45]. The integration of renewable energy sources like solar and fuel cells has also been investigated, particularly for small aircraft and unmanned aerial vehicles [46,47,48,49,50,51,52,53,54,55].

Energy management is a critical aspect of electrified aircraft systems. Various strategies have been proposed, including rule-based methods [56,57,58,59], optimization-based approaches [60,61,62,63], and artificial intelligence techniques [64,65]. These aim to optimize power distribution, minimize fuel consumption, and ensure stable operation across different flight phases.

Thermal management is another important consideration, as increased electrification leads to higher heat generation [66,67,68]. Integrated electro-thermal modeling and control approaches have been developed to address these challenges [69,70,71].

2.3. Predictive Modeling and Future Trends

Looking to the future, researchers are exploring concepts like distributed electric propulsion [72,73] and the integration of aircraft power systems with airport microgrids [74,75]. These developments could enable new operational capabilities and further improve overall system efficiency.

The control of electrified aircraft propulsion systems poses new challenges beyond conventional engine control [76,77,78,79]. These include managing interactions between gas turbine and electrical systems, handling negative impedance instability, and coordinating subsystems with different timescales [80,81]. Various control approaches have been investigated, including classical control [82,83,84,85,86], hierarchical control [87,88,89], robust control methods like H-infinity and sliding mode control [90,91], optimal control [92], and model predictive control [93,94,95].

The key areas for development include energy management strategies for hybrid-electric aircraft [96,97,98], improving the power density and efficiency of electrical machines, and enhancing thermal management capabilities. Integration of motor drives is another promising avenue for reducing system weight and improving overall performance [98,99,100].

Numerous conceptual designs explore the potential of electric propulsion. NASA’s N3-X design, with a turboelectric BLI system, aims for substantial fuel burn reduction and low NOx emissions [101,102]. The STARC-ABL design, a single-aisle narrow-body aircraft, demonstrates fuel savings through an aft-propulsor configuration, albeit with weight and complexity trade-offs [103]. The PEGASUS concept in the regional segment targets reduced operating costs through a parallel hybrid architecture [104]. In Europe, designs like Ce-Liner and VoltAir focus on achieving high efficiency with advanced battery and superconducting technologies [105]. DLR’s hybrid-electric turboprop design highlights the integration challenges and benefits of advanced airframe-propulsion synergies [106].

The electrification of aviation has been an active research area for over two decades, with increasing momentum in recent years. Reviews of related works provide insight into the ongoing technology challenges. In a comprehensive review, Hepperle covers the full landscape of electric aircraft configurations, components, and system considerations [107]. The review paper [108] explores the paradigm shift in aircraft propulsion due to electrification, acknowledging the design and sizing challenges in realizing these new concepts. The review [109] focuses on the role of the civil aviation sector in sustainable transportation, highlighting the emergence of electrified aircraft propulsion technologies as a key approach to achieving sustainable and decarbonized aviation. The review [110] provides insight into hybrid-electric and fully electric powertrains for aircraft, contributing to the “sky decarbonization” initiative. The paper [111] addresses the critical challenge of system integration in developing hybrid-electric and all-electric aircraft, including the retrofitting and redesign of existing aircraft. It emphasizes the need for integration tools in the conceptual design stage to tackle issues such as space utilization, power distribution between propulsion and secondary systems, electrification levels, safety, and thermal management.

2.4. Solar-Powered Electric Planes

Solar-powered electric planes are aircraft that use electric motors for propulsion, with electricity generated in part or entirely by solar panels installed on the aircraft’s surfaces. These solar panels capture sunlight and convert it into electrical energy, which is either stored in onboard batteries or used directly to power electric motors. Typically, solar-powered electric planes rely on battery storage systems to maintain operation when sunlight is insufficient, such as during nighttime or cloudy conditions. This type of aircraft is designed to reduce reliance on traditional fuel, enhancing sustainability and energy efficiency.

Solar-powered UAVs have attracted worldwide attention owing to their advantages such as environmental protection, zero fuel consumption, long endurance, and low noise [112,113,114,115,116]. Low-altitude solar-powered convertible unmanned aerial vehicles are a type of electric UAV that combines the advantages of the solar-powered fixed-wing UAV and the rotorcraft, which can realize the task requirements of vertical take-off and landing, long endurance, and multiple hovers [117,118,119,120]. New designs should consider solar irradiance, aircraft parameters, aerodynamics, the airfoil section, mission profile, mass estimation, and others [121].

While the related works on electric aviation provide valuable insight, they are not without limitations. Many studies tend to concentrate heavily on the technological aspects of electric aviation, such as advancements in battery technology or electric propulsion systems. While these are undoubtedly critical areas, such a focus can sometimes lead to an underestimation of market realities, consumer acceptance, and operational challenges. There is often a gap in the exploration of comprehensive economic feasibility and viable business models for electric aviation. Studies may overlook the importance of consumer perception and social acceptance.

The taxonomy-based approach to electric aviation analysis discussed in this paper offers an original, multifaceted, and adaptable framework that provides a comprehensive view of the field. Its structured categorization, integration of diverse elements, regional applicability, and forward-looking perspective set it apart from existing works, making it a valuable tool for a wide range of stakeholders interested in the future of electric aviation.

3. Taxonomy-Based Approach for Comprehensive Study of Electric Aviation

In aviation, taxonomies are actively used to classify objects and events as an effective description tool. In 1999, the CAST/ICAO Common Taxonomy Team (CICTT) was established by the U.S. Commercial Aviation Safety Team (CAST) and the International Civil Aviation Organization (ICAO) [122]. Its main task is to develop and promote common terminology and definitions to describe aviation safety events. Examples of developed taxonomies include Hazard taxonomy [123] and Flight Phase taxonomy [124], which is a set of terms used by ICAO to categorize the operational phase during which an aircraft accident or incident occurred. Flight Phase taxonomy is part of the ICAO accident data reporting system (ADREP) [125]. There is FAA Order 8000.71—Aircraft Make, Model, and Series Taxonomy [126]—belonging to traditional types of aircraft. Newman proposed for discussion a taxonomy of one of the classes of vertical take-off and landing (VTOL) [127,128,129]. The classification of individual technologies underlying VTOL applications was discussed in the articles [130,131].

Unfortunately, while these existing taxonomies provide valuable frameworks, they are limited to a specific range of aviation problems and do not address the emerging class of aviation technology—electric aviation. This article is primarily aimed at filling this gap by developing comprehensive taxonomies that encompass the unique aspects and challenges associated with electric aviation, thereby contributing to the advancement of this new and rapidly evolving field.

Electric aviation represents a frontier of technological innovation, marked by rapid advancements and burgeoning research. Yet, despite the proliferation of scholarly articles and industry reports, a cohesive understanding of this field has remained elusive. This research seeks to bridge this gap by employing a methodical and scientific approach: the construction of comprehensive taxonomies.

Taxonomies, in this context, are systematic frameworks for categorizing and organizing the vast and varied elements within electric aviation. This approach serves multiple purposes.

Firstly, it provides a structured means to synthesize the burgeoning body of literature, making it accessible and comprehensible. By categorizing information into distinct but interconnected categories, this methodology aids in distilling complex concepts and diverse research findings into a coherent body of knowledge.

Secondly, this approach is instrumental in identifying and elucidating relationships among different aspects of electric aviation. It allows for a comparative analysis across various dimensions, such as technological developments, regulatory landscapes, market trends, and environmental impacts. Such analysis is crucial not only for understanding the current situation but also for forecasting future trends and challenges in the field.

The construction of taxonomies also fosters interdisciplinary collaboration and communication. Electric aviation sits at the confluence of numerous fields—engineering, environmental science, economics, and policymaking, to name a few. A unified framework enables stakeholders from these diverse domains to engage with each other more effectively, leveraging a common language and understanding.

The taxonomy-based approach underpins predictive modeling and scenario analysis. Predictive models assess the potential impacts of electric aviation on various factors such as market adoption, infrastructure requirements, energy consumption, and environmental outcomes. Predictive models help stakeholders to plan for future developments and identify optimal strategies for investment and policymaking. By categorizing current knowledge and identifying gaps, the taxonomies offer a foundation upon which future developments can be anticipated and planned for, both in terms of technological innovation and policy formulation. This methodology supports rigorous academic endeavors, such as meta-analyses and systematic reviews. By providing a comprehensive and organized overview of existing research, it enables scholars to conduct in-depth analyses of the literature, assess consensus areas, and pinpoint divergences or under-researched topics.

The methodology applied in the study, which involves constructing a set of taxonomies to systematize knowledge in the field of electric aviation, can be characterized as a structured, systematic approach to scientific research. This method can be justified scientifically in several ways (Figure 1):

• Taxonomies provide a structured way to categorize and organize a large body of knowledge, which is essential in a field like electric aviation where research and development are rapidly evolving. This systematic organization helps in identifying gaps in current knowledge and potential areas for further research.
• By creating categories within taxonomies, researchers can more easily compare different aspects of electric aviation, such as technology types, regulatory challenges, or market trends. This comparative analysis is fundamental to scientific inquiry, allowing for the identification of patterns, relationships, and inconsistencies.
• Taxonomies create a common language for researchers, industry professionals, and policymakers. This is particularly important in interdisciplinary fields like electric aviation, where experts from different areas (e.g., engineering, environmental science, economics) need to collaborate. Clear categorization improves the efficiency and clarity of communication among diverse stakeholders.
• With a well-structured taxonomy, researchers can more effectively model different scenarios and predict future developments in electric aviation. This is crucial for strategic planning, policy development, and investment in the field.
• Taxonomies allow for the aggregation and synthesis of existing research, making it easier to conduct meta-analyses and systematic reviews. These are important tools in scientific research for assessing the state of knowledge on a topic, determining consensus, and identifying areas where opinions or findings diverge.
• By systematically categorizing information, researchers can track the evolution of technology and industry practices over time. This historical perspective is important for understanding how the field has developed and where it might be headed.

The methodology of constructing taxonomies to systematize knowledge in the rapidly evolving field of electric aviation is scientifically justified owing to its ability to organize complex information, facilitate comparative analysis, enhance communication, aid in predictive modeling, support comprehensive reviews of literature, and track the evolution of the field. This approach not only contributes to a deeper understanding of the current state of electric aviation but also enables a good visualization of current and future research directions.

The originality of the approach used in this study, which constructs taxonomies in the field of electric aviation based on ideas expressed in various publications, lies in its systematic synthesis and the creation of a detailed, organized framework where previously there was none.

This approach has several key aspects that justify its standing as independent research and underscore the original scientific results obtained (Figure 2).

Taxonomies act as common reference points, fostering interdisciplinary collaboration by standardizing terminology and concepts. They enable clear communication, assist in performance benchmarking, and support businesses in identifying market trends and opportunities, thereby guiding strategic decisions and innovation.

The originality of this research approach lies in its ability to systematically synthesize fragmented knowledge into a coherent, structured framework, providing new insights and perspectives, identifying research gaps, and facilitating future research. This approach represents an original scientific contribution, not merely a compilation of existing literature but a transformative process that elevates the understanding of electric aviation to a new level, justifying its classification as independent and original research.

4. Results

Electric aircraft represent a complex emerging domain spanning many disciplines and subject areas. As research and development accelerates, it becomes important to establish standardized frameworks for discussing and categorizing the technologies, configurations, applications, and other aspects associated with electric flight.

This section aims to propose a set of taxonomies that provide insight into the electric aviation landscape. Specific taxonomies are presented covering aircraft configurations, operational parameters, and regulatory factors. Each provides a hierarchy of classifications and descriptors within its focal subject area.

Together, these taxonomies create a multidimensional framework for categorizing electric aircraft initiatives and understanding tradeoffs. They facilitate the structured analysis of technologies and informed discussion between disciplines. As the foundations for electric flight coalesce, these taxonomies can enable clearer communication and accelerate progress through a cohesive knowledge structure. They represent an early attempt at bringing order to this promising but complex domain.

4.1. Classification of Electrical Aviation Based on the Primary Source of Electrical Power

Electric aircraft can be categorized in several ways based on their technological and operational characteristics.

As the electric aviation sector evolves, it has branched into distinct subcategories, each tailored to meet specific operational needs and capitalize on the advantages of electric propulsion. Two useful taxonomies exist for classifying electric aircraft types—one based on the primary source of electrical power, and another on the overall aircraft design.

Figure 3 offers a taxonomy of EA subcategories based on the primary source of electrical power.

The development of electric aircraft relies fundamentally on the power supply that provides propulsive energy. As such, categorizing electric aircraft designs by their primary power source provides insight into key technology options and tradeoffs.

Based on power plant architecture, three main electric aircraft types emerge (Figure 3):

• Battery-electric aircraft utilize batteries as the sole energy storage and power source. Battery-electric aircraft use only rechargeable batteries as their primary source of energy to power electric motors for flight. These aircraft are typically limited in range due to current battery technology, but they offer benefits such as zero emissions during operation and lower noise levels. Batteries are recharged from an external source between flights. Current lithium-ion batteries offer high efficiencies but low energy density. This category encompasses aircraft that solely utilize batteries charged from an external source as their powerplant. Lithium-ion batteries are the dominant technology, providing high efficiencies but relatively low energy density compared to aviation fuel. For most designs, batteries are recharged while the aircraft is stationary between flights. Battery-electric aircraft are the most common type today owing to the maturity of lithium-ion technology. Limitations in energy density constrain range and payload capacity compared to conventional airplanes. Flight times under 1 h are typical. Ongoing improvements in energy density will expand capabilities over time.
• Hydrogen fuel cell-electric aircraft employ compressed hydrogen as an energy carrier, converting it to electricity via proton-exchange fuel cells onboard. These aircraft utilize hydrogen as an energy source, converting it into electricity via fuel cells to power electric motors. Hydrogen fuel cells offer a higher energy density compared to batteries, allowing for longer flight durations. However, they come with challenges such as the storage of hydrogen and the complexity of fuel cell systems. Fuel cells offer 2–3× the energy density of batteries but at a higher overall system complexity. These aircraft employ compressed gaseous hydrogen as the onboard energy carrier. The hydrogen is converted to electricity by proton-exchange membrane fuel cells distributed throughout the aircraft. Fuel cells offer 2–3× the energy density of batteries. Water vapor is the only byproduct. The primary challenges are storage of compressed hydrogen and the complexity of fuel cell systems. Cryogenic liquid hydrogen has also been proposed but introduces additional efficiency losses. Fuel cells may enable longer flight times measured in hours.
• Solar-electric aircraft supplement batteries with photovoltaic cells to directly convert solar irradiation to electricity for partial propulsion and battery recharging. Feasible for long endurance applications. This type combines batteries with photovoltaic cells spread across the aircraft surface to collect solar energy during flight. The photovoltaic cells provide partial power for propulsion and recharging of batteries. Solar aircraft are designed for very long endurance applications like high-altitude communications relays. Energy is limited to daytime operation under solar illumination. Wing structure design must account for photovoltaic cell integration.

This power source taxonomy provides a useful framework for evaluating the core technologies available for aircraft electrification. The optimal choice depends on many mission-specific factors, such as endurance needs, cost, complexity tolerance, and environmental goals. No single solution is universally optimal.

4.2. Classification of Electrical Aviation Based on the Overall Aircraft Design

In addition to power source, categorizing electric aircraft by their overall aerodynamic configuration provides further useful perspective.

Figure 4 offers a taxonomy of EA subcategories based on the overall aircraft design: conventional electric airplanes, electric Vertical Take-Off and Landing (eVTOL) aircraft, and electric Short Take-Off and Landing (eSTOL) aircraft.

Three major electric aircraft design categories include:

• Conventional electric airplanes as existing aviation platforms retrofitted with electric propulsion technologies. This subcategory extends the legacy of traditional fixed-wing aircraft, modified to be powered by electric motors. With designs that are familiar to the aviation industry, these aircraft are suited for a variety of roles, from training and recreational flying to regional commercial transport. The advantages of electric propulsion, such as reduced noise and lower operational costs, make these aircraft an attractive option for airlines and pilots alike.
• Electric Vertical Take-Off and Landing (eVTOL) aircraft—novel vertical take-off and landing concepts enabled by electric propulsion, such as multicopters. The eVTOL subcategory represents a transformative approach to aviation, with aircraft capable of taking off and landing vertically like a helicopter but with the efficiencies of fixed-wing flight. eVTOLs are at the forefront of urban air mobility, envisioned to alleviate congestion in metropolitan areas by taking transportation to the skies. Urban air mobility refers to the use of eVTOL aircraft for short-distance travel within urban areas with the aim of reducing traffic congestion and improving mobility by offering on-demand air taxi services and other innovative transportation solutions. eVTOLs are also being developed for cargo delivery and emergency services, demonstrating versatility across various applications.
• Electric Short Take-Off and Landing (eSTOL) aircraft use electric propulsion for short take-off and landing from small runways. eSTOL aircraft are designed to operate from shorter runways, expanding access to areas with limited infrastructure. They strike a balance between the range and speed of conventional aircraft and the versatility of VTOL designs. eSTOL aircraft could serve as a sustainable solution for regional travel, connecting smaller communities with larger transport hubs.

This design taxonomy considers how the aircraft’s shape, lift, and propulsion are integrated rather than power technology alone. It provides insight into how electric propulsion can enable new aviation paradigms beyond retrofits.

Electric aircraft span a wide range of potential configurations optimized for different mission profiles. Three discussed major electric aircraft archetypes include conventional electric airplanes, eVTOL aircraft, and eSTOL aircraft. While all utilize electric propulsion, they differ significantly in their design and operating capabilities.

Table 1. Comparison of the key attributes of the major electric aircraft types.

Feature/Characteristic	Conventional Electric Airplanes	eVTOL Aircraft	eSTOL Aircraft
Aircraft Type	Fixed wing	Variety of types including multirotor, tiltrotor, etc.	Fixed wing with STOL capabilities
Take-Off and Landing	Requires a runway	Vertical take-off and landing	Short runways or improvised airstrips
Range	Medium (typically less than conventional aircraft)	Short to medium (due to weight of vertical lift systems)	Medium to long (optimized for efficient cruise flight)
Energy Efficiency	High (like gliders in some designs)	Lower (due to energy needed for lift)	High (due to aerodynamic efficiency)
Speed	Moderate	Lower than fixed-wing airplanes	Moderate to high
Payload Capacity	Varies, generally less due to battery weight	Usually less due to lift system weight	Comparable to conventional aircraft of similar size
Infrastructure Requirements	Charging stations at airports	Vertiports or retrofitted helipads with charging stations	Charging stations, possibly with shorter or modified runways
Operational Environment	Airports and airfields	Urban environments, hospitals, rooftops	Rural and remote areas, regional airports
Primary Use Cases	Short-haul commercial flights, pilot training	Urban air mobility, air taxi services, emergency services	Commercial regional transport, cargo delivery
Technological Complexity	Moderate	High (due to the complexity of lift and control systems)	Moderate (requires advanced aerodynamics for STOL)
Regulatory Hurdles	Moderate (similar to conventional aircraft)	High (new and evolving regulations)	Moderate (must meet existing aviation standards)
Cost Efficiency	Potentially high due to lower operating costs	Varies, currently higher due to new technology	Potentially high due to operational flexibility
Market Readiness	Emerging	Early stages, with ongoing demonstrations	Emerging with some models in advanced testing
Noise Levels	Generally lower than conventional aircraft	Low, especially compared to helicopters	Lower than conventional aircraft, varies by design
Environmental Impact	Reduced emissions, quieter operation	Minimal local emissions, quiet operation	Reduced emissions, quieter operation
Safety Features	Conventional aviation safety features plus electric system redundancy	Multiple redundancy for lift systems, often autonomous flight capabilities	Conventional aviation safety plus potential for short-field emergency landings

compares some of the key attributes of these major electric aircraft types to highlight their differences.

Conventional electric aircraft represent the electrification of traditional fixed-wing aviation platforms through the integration of electric propulsion technologies. Within this broad category, further classification of conventional electric aircraft configurations can be described by the taxonomy presented in Figure 5.

This classification system provides a framework for understanding the diversity within the category of conventional electric airplanes, based on their design, features, and intended use. Each subcategory within this taxonomy represents a distinct segment of the electric airplane market, tailored to meet specific operational requirements and preferences.

At a high level, there are the following examples of conventional EA: regional airliners—Zunum Aero [132], Eviation Alice [133]; private and business aircraft—Bye Aerospace eFlyer [134]; small personal aircraft—Pipistrel Velis Electro [135]; aerobatic/racing—Airbus E-Fan [136], Extra 330LE [137], and others.

Electric vertical take-off and landing (eVTOL) aircraft represent a novel category of aviation vehicles made possible by advances in electric propulsion technologies. eVTOL designs incorporate multiple rotors, propellers, or ducted fans to enable vertical flight without long runways.

There are many possible eVTOL configurations. This diversity can be better understood by a taxonomy based on their lift/thrust architecture (Figure 6).

This taxonomy captures the variety within the eVTOL category, highlighting the array of designs and intended functions that characterize this emerging field of aviation. It provides a structured way to understand the different approaches to achieving vertical flight and the potential applications of these innovative aircraft.

At high-level taxonomy, there are following examples of eVTOL aircraft.

Within the multirotor group of eVTOL aircraft, for example, are the next quadcopters—Volocopter 2X [138], Ehang 184 [139]; hexacopter—Hexa by LIFT Aircraft [140]; and octocopter—Cora by Wisk Aero [141]. In the Lift + Cruise group within eVTOL aircraft designs, the following examples can be provided: Lilium Jet [142]; Bell Nexus [143]; XTI TriFan 600 [144]; Lilium Eagle [145], and others. In the Wingless Multicopter group of eVTOL aircraft designs, the following examples can be provided: Transcend Air Vy 400 [146]; SkyDrive SD-03 [147]; Joby S4 [148], and others. In the Tilt Wing/Rotor group within eVTOL aircraft designs, the following examples can be provided: Leonardo AW609 [149]; Skydrive SD-05 [150]; Bell V-280 Valor [151], and others. An example of the Lift + Cruise Hybrid Wing group within eVTOL aircraft designs is the Beta Technologies Alia [152].

Electric propulsion enables new aircraft configurations optimized for short take-off and landing (eSTOL) from runways under 1000 feet. These eSTOL designs incorporate lift-enhancing technologies and streamlined shapes for field length constrained operations. Several eSTOL configuration categories can be delineated based on their approach to achieving short take-off and landing performance (Figure 7).

This classification system outlines the various segments within the eSTOL category, delineating them by key features such as propulsion, size, and intended use, as well as the specific operational niches they aim to fill within the aviation industry. Here are some examples of eSTOL aircraft configurations: Electra Aero [153]; NASA X-57 Maxwell [154]; Harbour Air eBeaver [155], and others.

In this paper, the focus of the discussed issues in electric aviation primarily revolved= around manned electric aircraft, including battery-electric, hydrogen-electric, and solar-electric airplanes, as well as their subcategories, like eVTOL and eSTOL aircraft. The decision to not include unmanned aerial vehicles (UAVs) in the primary discussion was strategic and based on several key considerations:

• UAVs, or drones, often cater to vastly different market needs and applications compared to manned electric aircraft. While electric UAVs are crucial in sectors like surveillance, agriculture, delivery services, and photography, the discussed issues in electric aviation are centered on passenger and cargo transport, regional connectivity, and commercial aviation dynamics. These are areas where manned aircraft play a more direct and significant role.
• The regulatory and policy landscape for manned electric aviation is markedly different from that of unmanned aerial systems. Given that one of the paper’s aims is to delve into the policy implications and strategic recommendations for electric aviation, it was important to concentrate on areas where regulatory evolution is most pressing in the context of passenger and cargo transport. UAVs, while subject to regulatory considerations, operate under a different set of rules and frameworks.
• The infrastructure and technology developments necessary for supporting manned electric aircraft, such as charging stations, vertiports, and adaptation of existing airports, differ significantly from those required for UAV operations. The paper seeks to address specific challenges and advancements related to infrastructure for larger-scale electric aircraft, which is a critical aspect of developing electric aviation for regional connectivity and commercial operations.
• The primary objective is to explore the potential and challenges of electric aviation in enhancing regional transport networks and commercial air travel. This includes exploring the feasibility, market potential, and environmental impacts of electric aircraft in passenger and cargo transportation, areas where manned aircraft are central.
• Including UAVs in the discussion would have broadened the scope of the analysis considerably, potentially diluting the focus and depth of exploration into the specific challenges and opportunities of manned electric aviation. By concentrating on manned aircraft, the paper provides a more in-depth and targeted analysis of the issues most pertinent to this segment of the aviation industry.

4.3. Ecosystem of Electrical Aviation

To fully grasp the intricacies of the emerging field of electric aircraft, a comprehensive understanding of the electric aircraft ecosystem is essential. Gaining a holistic understanding of the electric aviation ecosystem requires looking beyond individual applications and technology innovations. It involves taking a systematic view that maps the relationships between the various stakeholders, use cases, and enabling technologies. A systematic perspective highlights the interdependencies, barriers, and incentives that tie these components together into a complex ecosystem. This allows more coordinated strategies for unlocking the sustainable growth of electric propulsion across aviation applications.

The electric aviation ecosystem encompasses a broad range of components, each playing a critical role in the development, operation, and sustainability of electric aircraft. This ecosystem can be categorized into several key segments (Figure 8).

The taxonomies of electric airplanes themselves were studied in the previous subsection.

The taxonomy of key stakeholders in the electric aircraft cluster is shown in Figure 9. Each of these stakeholders has a vested interest in the development, implementation, and progression of electric aviation. Their collective efforts and collaboration are what will propel the industry forward, making the dream of a cleaner, quieter, and more efficient mode of air transport a reality. The ecosystem thrives when these diverse players work in harmony toward the shared vision of a sustainable aviation future.

Collaboration among these categories of stakeholders is essential for the successful development, implementation, and growth of electric aviation.

To describe the taxonomy of the electric aviation ecosystem in terms of application and use, we would consider the following classifications, shown in Figure 10.

This taxonomy can help in categorizing the different aspects of electric aviation based on how they are applied in practice, ranging from the type of electric aircraft to its intended use, operational environment, flight profile, level of autonomy, market segment, and regulatory status.

The infrastructure needed to support the operation of electric aircraft involves several key components, each addressing different aspects of electric aviation. The taxonomy of these components shown in Figure 11.

This infrastructure must be developed cohesively and in tandem with the growth of electric aviation technology to ensure a sustainable, efficient, and safe transition to electric-powered flight.

Incorporating human factors into the taxonomy of the electric aviation ecosystem extends the classification to include elements related to personnel, training, user experience, and community engagement (Figure 12).

Incorporating human factors into the taxonomy recognizes the central role that people play in the successful integration and operation of electric aviation within the broader ecosystem. It ensures that as the industry evolves, it remains safe, efficient, and beneficial to all stakeholders involved.

Creating a taxonomy for components and systems within the field of electric aviation involves categorizing the various elements that are integral to the functioning of electric aircraft (Figure 13). This taxonomy not only helps in understanding the current state of technology but also aids in identifying areas for further research and development.

Each category and subcategory in this taxonomy represents a specific area of focus within the components and systems of electric aviation. This structured approach not only provides clarity on the current technological landscape but also opens avenues for innovation and improvement in the design and functionality of electric aircraft.

The taxonomy for flight operations in electric aviation categorizes the operational aspects and characteristics of electric aircraft, focusing on the operational performance, efficiency, and challenges specific to electric aviation (Figure 14). This taxonomy is essential for understanding how electric aircraft are operated and managed, and for identifying areas for operational improvements and advancements.

Each of these categories provides a structured view of the various operational aspects of electric aviation, highlighting both the capabilities and challenges inherent in this emerging field. Understanding these elements is crucial for the continued development and integration of electric aircraft into the broader aviation ecosystem.

The taxonomy for maintenance and safety in electric aviation is crucial for understanding the unique requirements and challenges associated with maintaining and ensuring the safety of electric aircraft (Figure 15). This taxonomy categorizes the key areas of focus in maintaining electric aviation systems and the strategies employed to ensure operational safety.

This taxonomy provides a comprehensive overview of the various facets of maintenance and safety in electric aviation. It underscores the unique considerations and practices necessary to maintain electric aircraft and ensure their safe operation, reflecting the evolving nature of technology and regulatory frameworks in this field.

The taxonomy for regulations and standards in electric aviation encompasses the diverse range of regulatory frameworks and standards that govern the development, certification, operation, and maintenance of electric aircraft (Figure 16). This taxonomy is crucial for ensuring that electric aviation progresses safely, efficiently, and in compliance with established norms.

This taxonomy highlights the multi-layered and comprehensive nature of regulations and standards in electric aviation, encompassing everything from airworthiness to environmental compliance. It reflects the need for a well-regulated framework to ensure the safe and sustainable development of this emerging field.

4.4. Main Directions of Scientific Research in Electric Aviation Area

The realm of electric aircraft is not just an engineering challenge, it is an extensive scientific endeavor that encompasses various fields of research. The scientific community is pushing the boundaries of knowledge and technology to transform the way in which we understand and utilize electric power in aviation. Electric aviation is at the confluence of interdisciplinary innovation, drawing upon advances in materials science, electrical engineering, aerodynamics, and environmental science.

This subsection delves into the areas of scientific research that form the backbone of electric aircraft development. The general taxonomy of main research activities in electric aviation domain is shown in Figure 17.

4.4.1. Advances in Battery Technology

At the heart of electric aircraft is the quest for high-energy, lightweight, and safe battery technology. Researchers are exploring beyond conventional lithium-ion batteries to next-generation energy storage solutions, such as solid-state batteries and lithium-sulfur technologies.

The quest for the ideal aviation battery centers on maximizing energy density—the amount of energy stored per unit weight. Recent breakthroughs in battery chemistry, including the development of lithium-sulfur and solid-state batteries, offer significant improvements over traditional lithium-ion batteries. These novel chemistries promise not only higher energy densities but also reduced risks of overheating and potential failure.

Lithium-sulfur batteries are emerging as a strong contender, primarily due to their higher theoretical energy density compared to lithium-ion batteries. They utilize lightweight sulfur as the cathode material, which can store more energy per unit mass. Research in this area has been focused on overcoming the challenges of cycle life and stability, with new electrolyte formulations and electrode architectures increasing the viability of these batteries for aviation applications.

Solid-state batteries represent another forefront of battery innovation. By replacing the liquid electrolyte with a solid, these batteries offer improved safety and the potential for even greater energy densities. Advances in solid electrolytes, such as ceramic or glass materials, have addressed issues of conductivity and manufacturability, edging solid-state batteries closer to commercial reality.

The practicality of electric aircraft is also bound to their ability to recharge quickly. Innovations in charging technology aim to minimize downtime and enable rapid energy replenishment. This includes the development of ultra-fast charging batteries that can significantly reduce the time required to reach full capacity, as well as the integration of wireless charging concepts that could facilitate easier power transfer.

The longevity and reliability of batteries in aviation are paramount. Advanced battery management systems are being developed to optimize performance, extend lifespan, and ensure safety during flight. These systems monitor the health of each cell and manage charging and discharging processes to prevent degradation. Furthermore, research into the lifecycle management of batteries, including recycling and repurposing strategies, ensures that battery technology advances sustainably.

4.4.2. Innovation in Electric Propulsion Systems

Electric propulsion systems refer to the mechanisms that use electrical energy to power the engines or motors of an aircraft. In electric aviation, these systems replace traditional combustion engines with electric motors that drive propellers or fans. These systems are generally powered by batteries, hydrogen fuel cells, or solar energy. Key benefits include higher energy efficiency, lower emissions, and reduced noise compared to conventional propulsion systems. Electric propulsion represents a radical departure from traditional jet engines, necessitating rigorous research to optimize performance and efficiency. This direction consists of the scientific efforts in developing advanced motor designs, high-efficiency power electronics, and innovative cooling techniques that enable electric aircraft to meet the demands of flight.

Electric propulsion systems offer a stark contrast to their combustion-based counterparts, eliminating the need for burning fossil fuels and thereby reducing emissions. Innovations in this sector are multifaceted, involving advances in electric motors, power electronics, and integration techniques that are reshaping aircraft design.

The electric motor is the heart of the electric propulsion system, converting electrical energy into mechanical power. Researchers are pushing the limits of motor efficiency and power-to-weight ratios, developing motors with high-temperature superconductors and advanced magnetic materials. These motors are designed to be lightweight, with minimal losses and high reliability, which is crucial for their adoption in aviation.

The role of power electronics in electric propulsion cannot be overstated. They control the flow of electrical energy, managing high loads with precision. Advances in semiconductor materials, such as silicon carbide (SiC) and gallium nitride (GaN), have led to smaller, lighter, and more efficient power electronic systems. These components are vital for handling the rapid switching and high voltages typical in aviation applications.

Effective cooling systems are essential for maintaining performance and ensuring the longevity of electric propulsion systems. Innovations in this area have led to the development of advanced thermal management solutions, including liquid cooling systems that are integrated into the motor design. These systems not only keep temperatures within safe operating limits but also contribute to the overall efficiency of the propulsion system.

Electric propulsion systems allow for a high degree of flexibility in airframe integration. Distributed propulsion, where multiple motors are used across the aircraft, offers novel ways to improve aerodynamics and reduce noise. Research is exploring the benefits of embedding motors in wings or fuselages, enhancing lift and reducing drag, a concept that could lead to entirely new aircraft designs.

A promising area of research in electric propulsion is the ability to harvest and regenerate energy. Technologies such as regenerative braking, which captures energy during descent or landing, are being adapted for aviation. This not only improves overall efficiency but also extends the range of electric aircraft, addressing one of the primary challenges in electric aviation.

4.4.3. Aerodynamic Design for Efficiency

The integration of electric propulsion systems into aircraft design poses unique aerodynamic challenges. Research in this area seeks to maximize energy efficiency through airframe integration, where propulsion and structure are harmoniously designed. This subsection is oriented toward discussing the cutting-edge research in aerodynamics that aims to enhance the performance and efficiency of electric aircraft.

The design of an electric aircraft’s airframe is a critical factor in its aerodynamic efficiency. The goal is to minimize drag—a force that opposes the aircraft’s motion through the air—while maximizing lift, which allows the aircraft to ascend and remain aloft. Innovative airframe designs are incorporating sleek, streamlined shapes and new materials to reduce weight and drag, thereby improving energy efficiency.

The use of advanced lightweight materials such as carbon fiber composites plays a significant role in improving aerodynamics. These materials offer high strength-to-weight ratios, allowing for thinner wings and fuselage profiles without compromising structural integrity. In addition, the use of these materials can lead to a reduction in the aircraft’s overall weight, thus requiring less energy to achieve and maintain flight.

Wing design is another critical aspect of aerodynamics. Researchers are exploring various wing configurations, such as blended wing bodies and adaptive wing designs, which can change shape during flight to optimize aerodynamic performance. Such innovations can lead to significant improvements in the lift-to-drag ratio, which is crucial for the efficiency and agility of electric aircraft.

The integration of propulsion systems into the aircraft’s design also affects aerodynamic efficiency. Distributed propulsion, where multiple electric motors are placed across the aircraft, offers unique opportunities to enhance lift and reduce drag. By placing propellers or fans along the wings or fuselage, electric aircraft can benefit from increased lift generated by the airflow over the surfaces, a concept known as boundary layer ingestion.

Advances in computational fluid dynamics (CFD) are enabling designers to simulate and analyze airflow around the aircraft with high precision. These simulations help to identify areas where airflow can be optimized, leading to design modifications that reduce drag and improve efficiency. The use of CFD in the design process ensures that the final aircraft shape is as aerodynamically efficient as possible.

In the pursuit of efficiency, extensive testing and validation are necessary. Wind tunnel testing, along with flight testing of prototypes, provides empirical data to validate and refine aerodynamic models. This real-world testing is crucial to understanding how design changes affect performance and to ensuring that theoretical improvements translate into tangible benefits.

4.4.4. Environmental Impact Assessments

Sustainability refers to the overall environmental impact of electric aviation, focusing on reducing carbon emissions, noise pollution, and resource consumption throughout the aircraft’s lifecycle—from design and manufacturing to operation and recycling. It is a key driver in the development of electric aircraft as a response to global climate change goals. As sustainability is a key driver of electric aviation, scientific research also extends to environmental impact studies. These studies assess the lifecycle emissions of electric aircraft, from manufacturing to operation to decommissioning.

The environmental benefits of electric aircraft are often highlighted as one of the primary motivations for their development. Nevertheless, a comprehensive environmental impact assessment (EIA) is crucial to understanding the full ecological footprint of these technologies, from production through to operation and eventual decommissioning.

A key component of environmental impact assessments is lifecycle analysis (LCA). This process evaluates the environmental impacts associated with all the stages of an aircraft’s life, including material extraction, manufacturing, operation, maintenance, and end-of-life disposal or recycling. LCAs are essential to ascertain whether electric aircraft contribute to a net reduction in environmental impact compared to conventional aircraft.

The environmental impact of manufacturing electric aircraft is complex. The production of advanced batteries and the extraction of materials required for high-performance electric motors and lightweight airframes can have significant environmental implications. EIAs in this realm consider the sourcing of raw materials, the energy required for manufacturing processes, and the potential for recycling or repurposing materials at the end of their life.

Electric aircraft promise significant reductions in operational emissions. Unlike traditional aircraft, they produce no direct combustion emissions during flight, which could lead to improved air quality and reduced greenhouse gas emissions. EIAs explore these benefits quantitatively, considering the source of the electricity used to charge the aircraft’s batteries and the potential for renewable energy integration.

Noise pollution is a significant environmental concern for communities near airports. Electric aircraft are generally quieter than their combustion-engine counterparts, which could lead to less noise pollution and associated health benefits. Environmental impact assessments analyze noise levels across different phases of flight and predict the potential reduction in noise footprint.

The disposal and recycling of electric aircraft components, particularly batteries, are critical end-of-life considerations that must be addressed in EIAs. Proper disposal methods are essential to prevent environmental contamination, while recycling can help to reduce the demand for raw materials and energy consumption.

EIAs are also a tool for ensuring regulatory compliance. They help manufacturers and operators to demonstrate that electric aircraft meet environmental regulations and standards. The role of EIAs in fulfilling national and international environmental policies and their influence on the certification and commercialization of electric aircraft are important directions of EA study.

4.5. Full Lifecycle of Technology

The full lifecycle of a technology, particularly in the context of electric aviation, encompasses several distinct stages from initial concept through to disposal and recycling. A taxonomy of this lifecycle could include the content areas shown in Figure 18.

This taxonomy not only ensures a comprehensive understanding of a technology’s progression over time but also helps stakeholders anticipate the needs and challenges at each stage. For electric aviation, this would involve detailed planning and coordination across a variety of domains, from R&D to regulatory compliance, and from manufacturing to end-of-life recycling, to ensure sustainable and successful technology management throughout its full lifecycle.

4.6. Importance of Electrical Aviation for Regional Development

4.6.1. The Adoption of EA for Regional Transport Connections in the European Union

The European Union (EU) has long been at the forefront of advocating for sustainable transportation solutions. With its commitment to green policies, the EU has recognized the potential of electric aviation as a cornerstone for enhancing regional transport connections [156]. Electric aviation offers a promising avenue to bolster regional transport, particularly in areas where connectivity remains a challenge. This essay explores the strategies for enhancing the adoption of electric aviation within the EU, focusing on passenger and cargo transportation in regions that stand to benefit significantly from improved linkages.

Many regions within the EU, especially those that are geographically isolated or less economically developed, suffer from inadequate transport connections. The current regional transport network is often characterized by longer travel times, limited-service frequency, and reliance on traditional, carbon-intensive aircraft that are not only environmentally detrimental but also economically inefficient. These factors collectively impede socio-economic growth, hinder accessibility, and restrict the free movement of goods and people—a fundamental principle of the EU.

Electric aviation emerges as a sustainable alternative that can bridge the connectivity gap across the EU. With lower operational costs, reduced noise levels, and zero direct emissions, electric aircraft—including battery-electric, hydrogen-electric, and hybrid models—can operate shorter routes cost effectively and more frequently. They can service small and medium-sized airports, many of which are currently underutilized, thus unlocking the economic potential of numerous regions.

Developing the necessary infrastructure is a critical step toward the widespread adoption of electric aviation. This includes the establishment of charging stations, vertiports for eVTOL aircraft, and hydrogen refueling facilities. The EU’s role in standardizing infrastructure development is crucial to ensuring interoperability and safety across member states. A harmonized approach can lead to more efficient use of funds, better planning, and faster implementation.

Electric aviation can reshape regional connectivity by reducing travel times and making remote areas more accessible. Enhanced connectivity directly contributes to economic integration, fostering trade, tourism, and investment. The EU’s cohesion policy, aimed at reducing disparities between regions, can be a significant driver in adopting electric aviation, emphasizing its role in regional development.

The environmental benefits of electric aviation align with the EU’s climate goals, but its social impact is equally important. By enhancing connectivity, electric aviation can promote social inclusion, provide greater access to economic opportunities, and improve quality of life.

4.6.2. Predictive Models of Regional Market Development

The geographical and economic characteristics of any region present unique opportunities for the implementation of electric aviation. Creating predictive models for regional market development, especially in the context of accelerating the adoption of electric aviation, requires a structured approach to analyze various influencing factors and forecast market dynamics. Figure 19 presents the taxonomy of the main research components for such predictive models.

By systematically analyzing the categories shown in Figure 19, predictive models can offer insight into how the regional market for electric aviation might develop and identify the levers that could accelerate clarity and adoption. These models would enable stakeholders to make informed decisions, allocate resources efficiently, and plan strategically for the future of regional air transport.

4.7. Business Models for Electrical Aviation

Business models in the context of electric aviation describe the strategies and frameworks used by companies to generate revenue and profit from electric aircraft technologies. These models may include selling or leasing aircraft, offering air taxi services, integrating urban air mobility solutions, or developing infrastructure like charging stations and maintenance facilities. The models also emphasize partnerships with stakeholders, regulatory adaptation, and environmental considerations to meet the growing market demands for sustainable air travel. Creating business models for aviation stakeholders in the context of electric aviation involves a taxonomy that encapsulates various operational, financial, and partnership structures. This taxonomy is shown in Figure 20.

By employing this taxonomy, aviation stakeholders can develop robust and comprehensive business models that cater to the dynamic nature of the industry, particularly as it transitions to include electric aviation. These models are designed to facilitate strategic decision making, foster sustainable practices, and enhance competitiveness in the market.

5. Discussion

5.1. Comparative Analysis of Electric vs. Conventional Aircraft Preferences

The electric aircraft industry represents a dynamic and transformative segment of aviation, marked by rapid technological advancements and a growing commitment to sustainable transportation.

At the core of the electric aircraft industry’s growth are several key technological drivers. Advances in battery technology, particularly in energy density and charging speed, have been pivotal. Additionally, innovations in electric motors, which offer high efficiency and low maintenance, are crucial for the practical application of these aircraft.

The market for electric aircraft is rapidly evolving, with a diverse range of players from established aerospace giants to innovative startups.

While the prospects of electric aircraft are promising, the industry faces a myriad of challenges. These include technical hurdles such as range limitations and payload constraints, infrastructural needs like specialized charging stations and maintenance facilities, and regulatory hurdles. Conversely, this landscape presents numerous opportunities, such as the potential for new business models, urban air mobility solutions, and a significant reduction in aviation’s environmental footprint.

The comparison in

Table 2. Comparison of preferences in the use of electric and conventional aircraft.

Aviation Applications	Electric Aviation Preferable	Conventional Aviation Preferable
Short-Haul Passenger Flights	Ideal for short distances due to limited battery range.	Longer routes where current battery technology cannot sustain the required range.
Urban Air Mobility	eVTOLs perfect for intra-city travel and congested areas.	Less efficient due to noise and fuel consumption.
Cargo Transport	Suitable for lightweight, time-sensitive cargo.	Better for heavy and long-haul cargo due to higher payload capacity.
Regional Connectivity	Efficient for connecting small and remote airports.	Conventional aircraft are preferred for longer regional routes.
Medical/Emergency Services	Quick deployment and lower noise levels are advantageous in emergency situations.	Longer range missions and heavier medical equipment transport.
Tourism and Sightseeing	Quieter operation is less intrusive for natural and urban scenic flights.	Longer sightseeing routes that exceed electric range capabilities.
Environmental Monitoring	Zero emissions and quieter operation are beneficial for ecological studies.	Extended range and endurance missions in remote areas.
Training and Education	Ideal for short-duration training flights with lower operational costs.	Training requiring longer flight times and diverse operational conditions.
Agricultural Applications	Effective for small-scale, precision agriculture operations.	Large-scale agricultural operations requiring longer flight times and heavier payloads.
High-Altitude Long-Endurance (HALE) Missions	Solar-electric aircraft could excel in long-duration, high-altitude surveillance and research.	Conventional aircraft for missions requiring heavy payloads and rapid response.

shows the applications in which electric aviation is preferable and where conventional aviation retains a higher application potential.

This table demonstrates that while electric aviation offers considerable advantages in terms of sustainability and efficiency for short-range and specialized applications, conventional aviation continues to be more practical for long-haul flights, heavy cargo transport, and missions requiring extended range and endurance. The choice between electric and conventional aviation ultimately depends on the specific operational requirements, range necessities, and environmental considerations.

The accessibility and practicality of electricity as an energy resource, particularly when derived from renewable sources, is an additional significant factor driving interest in electric aviation. This aspect becomes even more pronounced in contexts in which the delivery of traditional aviation fuel is logistically challenging or economically impractical. This synergy not only addresses the practical aspects of fuel accessibility but also aligns with broader environmental and economic objectives, making electric aviation an attractive and viable option in various regional contexts.

The logistical challenges associated with the use of traditional aviation fuel stand as an important factor that bolsters the case for electric aviation. These difficulties are particularly pronounced in remote, isolated, or environmentally sensitive regions, where the transportation, storage, and handling of aviation fuel entail complex, costly, and often risky logistical operations.

A study focused on developing taxonomies in the field of electric aviation offers several distinct advantages. These benefits play a crucial role in enhancing understanding, fostering innovation, and guiding strategic decisions in this rapidly evolving sector.

Taxonomies enable systematic comparisons and performance benchmarking within electric aviation, aiding in the identification of best practices and technological advancements. They inform policymakers and businesses by offering a comprehensive overview of the field, supporting strategic planning, innovation, and the development of relevant policies and standards.

5.2. Study Limitations

A study oriented toward developing taxonomies in electric aviation, while valuable, may face several limitations. These limitations are crucial to acknowledge for a comprehensive understanding of the study’s scope and potential areas for further research:

• Electric aviation is a fast-evolving field. Taxonomies developed based on current knowledge might become outdated as new technologies and innovations emerge.
• The process of categorizing information into a taxonomy can be subjective. Different experts might have varying opinions on how to classify certain aspects, which could affect the taxonomy’s structure and utility.
• Electric aviation intersects with various disciplines, like engineering, environmental science, policy, and economics. Integrating these diverse perspectives into a coherent taxonomy can be challenging.
• There is a balance to be struck between the complexity and user-friendliness of a taxonomy. Overly complex taxonomies might be thorough but less practical for stakeholders who are not experts in the field.
• While taxonomies are excellent for organizing existing knowledge, they are less effective in predicting future trends or prescribing specific courses of action.

5.3. Future Research Directions

Understanding these limitations is essential for effectively utilizing the taxonomies in research and practical applications, and for guiding future studies to refine and expand upon the initial framework.

Based on the discussions so far around the current gaps, limitations, and growing knowledge base in electric aviation, some potential directions for future research include:

• Continued research on improving battery energy density, charging rates, safety, and lifespan through new chemistries and innovations; advanced battery chemistries, such as lithium-sulfur and solid-state batteries, which promise higher energy densities and faster charging capabilities; the potential for supercapacitor integration and novel propulsion methods, including ionic wind propulsion for transformative avenues for aircraft design and efficiency.
• Analyzing the required faster charging technologies, networked systems, and grid integration solutions to enable maturation.
• Investigating optimized component configurations, hybrid propulsion integrations, and heat management for increased performance.
• Exploring airframe structural changes to better accommodate electrification components while preserving aerodynamics.
• Developments in materials science, such as carbon nanotube composites and 3D printing technologies, which could lead to lighter, stronger, and more cost-effective aircraft components, and the impact of these materials on manufacturing processes, lifecycle sustainability, and aircraft recycling.
• Expanded modeling and lifecycle analysis on total costs, commercial viability, and sustainability.
• Research into the most effective market incentives, infrastructure investment models, and certification standardization approaches that need shaping.
• Economic models and market shifts; the influences of subscription-based services, pay-per-use models, and the sharing economy on the market dynamics of electric aviation; and the economic incentives and policies that could stimulate market growth and innovation.
• Understanding customer perceptions, community concerns, and labor force dynamics around new aircraft.
• Collaboration, global initiatives and international collaboration and their vital role in shaping the future of electric aviation; the importance of cross-border partnerships, standardization efforts, and joint ventures in research and development; and the role of international bodies, such as the International Civil Aviation Organization (ICAO), in fostering innovation and harmonizing regulations.
• Smart infrastructure and urban and regional air mobility, the evolution of urban landscapes to accommodate electric aviation, including smart vertiports, integrated traffic management systems, and the public infrastructure needed to support widespread adoption.
• Artificial intelligence and autonomous operations and their role in the future of electric aviation, the integration of autonomous systems in electric aircraft from pilot assistance technologies to fully autonomous operations, alongside the regulatory and ethical considerations they entail.

These research directions are not only crucial for addressing the technical and operational challenges of electric aviation but also for ensuring its sustainable and socially responsible development. The focus is oriented toward the study, design, and creation of an ecosystem that supports the widespread adoption and integration of electric aviation into the global transportation network.

5.4. Taxonomies as Background for Regulatory Frameworks and Documents for Electric Aircraft

The regulatory landscape for electric aircraft is still in its formative stages, as this new mode of aviation presents unique technological, operational, and environmental challenges. Approaches to regulating electric aircraft are currently being developed by various aviation authorities and organizations. While some initial guidelines and standards have been proposed, there remains a significant need for comprehensive regulatory frameworks that address the full spectrum of electric aviation, including certification, airspace integration, safety, environmental impact, and infrastructure requirements.

Several studies and regulatory documents have made early attempts to create foundational approaches to governing electric aircraft. For instance, the European Union Aviation Safety Agency (EASA) has issued Special Condition SC E-19 to address the certification requirements for Electric and/or Hybrid Propulsion Systems (EHPS) used in manned and unmanned aircraft [157]. The document provides guidance for designing and certifying EHPS by focusing on areas such as system configuration, safety assessment, endurance testing, vibration control, fire protection, and system integration. This regulation is forward-looking, addressing the complex interactions between EHPS components, aircraft design, and operational demands, setting the groundwork for the future certification of advanced electric and hybrid propulsion technologies.

The document [158] outlines the first special airworthiness conditions issued by the Federal Aviation Administration (FAA) for the certification of the magni350 and magni650 electric engines developed by magniX USA, Inc. (Everett, WA, USA). These engines represent a novel design compared to traditional aircraft engines that rely on aviation fuel, as they utilize electric motors, controllers, and high-voltage systems for propulsion. The document introduces special conditions that address hazards specific to electric engines, such as high-voltage components, electromagnetic interference, and failure modes that differ from traditional aviation engines.

The International Civil Aviation Organisation (ICAO) working paper [159] calls for the development of airworthiness requirements for electric powered aircraft. Recognizing the rapid advancement and increasing importance of electric aviation, the paper highlights the need for harmonized global certification standards to ensure the safe integration of electric propulsion technologies into the aviation sector. The paper emphasizes that current airworthiness standards do not fully address the unique characteristics and safety requirements of electric aircraft, particularly those powered by batteries, fuel cells, and solar energy. To address this issue, the paper recommends that ICAO task its Airworthiness Panel with developing global guidance materials and airworthiness standards for electric powered aircraft. This initiative would harmonize certification policies across states, facilitating the cross-border operation of electric aircraft and promoting aviation safety. Harmonized standards would also support the growth of the electric aviation industry and contribute to global environmental goals by reducing the aviation sector’s carbon footprint.

While these documents are valuable, they remain limited in scope and are still evolving. A more structured, holistic approach to regulation is needed to ensure the safe and efficient integration of electric aircraft into the global aviation ecosystem.

The taxonomies proposed in this article offer a comprehensive and systematic framework that can serve as a foundation for the effective development of such regulatory documents. By categorizing the various technological, operational, and infrastructural aspects of electric aviation, these taxonomies provide a clear structure for identifying key areas that require regulation.

The taxonomies presented in this study provide a robust and adaptable framework that can assist policymakers and aviation authorities in developing the comprehensive regulatory frameworks necessary for the widespread adoption and safe operation of electric aircraft. As the electric aviation industry continues to evolve, this structured approach can ensure that regulations remain forward-looking and capable of addressing the dynamic challenges posed by this new transportation segment.

6. Conclusions

Electric aircraft technology has advanced significantly in recent years through ongoing scientific research and practical developments. This article provides an overview of the current state of electric aircraft technology in terms of research and real-world applications.

The transition toward sustainable transportation has marked the rise of electric aviation as a significant area of technological innovation and research. However, the complexity and multidisciplinary nature of the field have necessitated a methodical approach to organize and understand its vast and diverse body of knowledge. This article presents a series of structured taxonomies that categorize the components, systems, operations, maintenance, safety, regulations, and scientific research activities within the domain of electric aviation. These taxonomies provide a systematic framework that not only clarifies the current landscape but also guides future research and development efforts. Through a detailed examination of each taxonomy, the paper identifies key technological drivers, market dynamics, infrastructural needs, and regulatory frameworks shaping the industry. It discusses the challenges and opportunities inherent in electric aviation, offering a balanced view of its potential to revolutionize regional and global transportation networks. Furthermore, the article explores the implications of electric aviation for regional development, underscoring its role in enhancing connectivity and socio-economic integration. Predictive models for market development and strategic business models for stakeholders highlight the practical applications of the taxonomies developed. This comprehensive approach aims not only to advance scholarly discourse but also to inform policymakers and industry leaders, fostering the growth of electric aviation in alignment with global sustainability goals.