Clearing the Air: Opportunities & Hurdles in Electric Aviation
While sustainable aviation fuel (SAF) is expected to play the largest role in decarbonizing aviation, advancements in other technologies will also be critical for achieving net-zero emissions, including electric aviation. Though the portion of the aviation market that could be replaced by electric aircraft is relatively small, this technology offers unique benefits for certain flight routes that make it worth pursuing. Similar to how the environmental footprint of SAF is calculated, the greenhouse gas (GHG) emissions of electric flight operations would need to be based on a well-to-wake (WTW) basis, which would consider emissions associated with electricity production and battery replacements.
Electric aircraft fall into three main categories: fully electric, hybrid-electric, and retrofits. Each category represents a different approach to reducing emissions and has a place in advancing electric aviation.
Electric Aircraft Categories
Fully Electric Aircraft
Fully electric aircraft are powered solely by electric motors, which drive propellers or sets of small fans. The energy is stored in batteries. Since no combustion takes place, operational CO2 emissions are eliminated. However, lifecycle emissions depend heavily on how the electricity is generated. In an ideal scenario, using fully renewable energy sources could bring these emissions close to zero.
Several companies are leading the way in this field, particularly in the development of smaller electric vertical takeoff and landing (eVTOL) aircraft. Notable players include Joby Aviation, Archer Aviation, Supernal, Lilium, Volocopter, and Eve Air Mobility, while others like Heart Aerospace are focusing on fully electric regional commuter planes, air taxis, and light cargo aircraft.
Hybrid Electric Aircraft
A hybrid solution combines the advancements of electric propulsion with the power of fueled engines, like traditional internal combustion engines (ICE) or hydrogen options. For example, the two can be used together during takeoff to maximize thrust, while the combustion engine can be throttled back during cruise, reducing overall fuel consumption. While emissions are lower than conventional aircraft, they are not eliminated. Hybrid technology is viewed as an essential step toward achieving full electrification in larger aircraft.
Retrofits and Conversions
Another approach to electric aviation is converting existing ICE aircraft to electric. This method, while still emerging, offers a way to accelerate the transition to electric aviation by repurposing older fleets. A prominent example is Canada’s Harbour Air, which, in collaboration with magniX, is working to convert its seaplane fleet into the world’s first fully electric commercial aircraft fleet.
How Does Electric Aviation Fit into Decarbonization?
As part of the global push toward net-zero emissions, electric aviation plays a small but significant role. According to the International Air Transport Association (IATA), 13% of the emissions reductions needed to achieve net-zero in aviation will come from new technologies, including electric and hydrogen-powered aircraft. However, these aircraft are expected to be most effective on shorter routes due to the current limitations of battery technology. Batteries, being heavy, make long-range electric flight challenging, for now.
Currently, electric aircraft are being developed to handle very small flights up to 500 miles. Given that around 17% of airline emissions are created by short-haul flights (up to 600 miles), these shorter routes would supply a significant opportunity for electric aircraft replacement. However, the majority of emissions come from longer flights and even by 2050, it is expected that electric aircraft will contribute to a minority of CO2 emission reductions being focused on the smaller operation level:
Description: “A simplified view of which energy options might be able to contribute to the reduction in CO2 emissions from air transport in which time period. This generally indicates when the technology may be commercially available, but not widespread use throughout the fleet.”
Source: ATAG Waypoint 2050 2nd edition: September 2021 Full Report & Summary.pdf (aviationbenefits.org)
Battery Technology
For the past 30 years, batteries have become more powerful and compact. One of the biggest challenges in battery development is balancing energy density with power density. Energy density determines how much energy a battery can store, while power density affects how quickly that energy can be discharged. Electric aircraft, especially eVTOLs, require high power density for takeoff and landing, alongside sufficient energy density to cover their range and reserves. Achieving both remains a major technical hurdle.
Rechargeable lithium-ion batteries, known for their high specific energy and energy density, are the leading choice today, powering everything from smartphones to electric vehicles. The specific energy density of a battery measures how much energy it can store per unit of mass, typically expressed in watt-hours per kilogram (Wh/kg). Current battery technology can store up to 250 Wh/kg. Since their introduction in 1991, the specific energy and energy density of lithium-ion batteries has more than tripled. But by comparison, Jet A fuel still far exceeds this, with nearly 50 times the specific energy (12,000 Wh/kg) of batteries and about 14 times the energy density (9,690 Wh/L).
Other emerging battery technologies, such as all-solid-state and aluminum-air batteries, are being researched as potential breakthrough technologies, though each comes with its own limitations. Current battery technology is still developing, and the future of electric planes depends heavily on further advancements.
Needs & Challenges
Energy Density (Battery Capacity): Energy density, covered above, is a key factor in determining aircraft range. While fast-charging capabilities and battery cycle life are advancing, energy density remains a challenge. This is why much of the focus on electric aviation has been on smaller aircraft like VTOL drones and air taxis, which are weight optimized and carry fewer passengers or cargo.
Power vs Weight: The heavier the aircraft, the more power it needs to fly. Electric aircraft face unique weight challenges because electric drives, cables, and cooling systems weigh significantly more than traditional gas turbines. Unlike conventional planes, which get lighter as fuel burns off during flight, electric aircraft maintain the same weight throughout, making efficient power management critical. This results in smaller aircraft with reduced passenger capacity and shorter ranges, especially when factoring in reserve fuel requirements.
Battery Cooling: Batteries in electric aircraft must be cooled to prevent overheating, adding weight and drag to the aircraft. Larger aircraft will need liquid cooling systems for both batteries and electric drives. Charging infrastructure, which will handle high currents, also requires robust cooling to manage the heat generated during quick charging sessions.
New Infrastructure: Electric aviation infrastructure faces two main challenges: access to sufficient power and an efficient, common charging interface. Most industry leaders currently rely on the Combined Charging Standard (CCS), a common EV standard that simplifies the customer experience and spreads infrastructure costs across the sector. However, as electric aircraft battery capacity grows, megawatt-level charging will be necessary. A Megawatt Charging Standard (MCS) is being developed to meet this future need, but high-power charging will require thicker conductors, robust cooling systems, and careful planning to manage grid impacts. FBOs and ground support will need to ensure their facilities have access to sufficient power by coordinating with utilities and charging providers to develop scalable infrastructure that can meet the demands of growing fleets and larger aircraft.
Capital-Intense: Electric aircraft development requires significant capital, with some estimates running in the billions per aircraft certification. Governments, such as Norway's, have stepped in to subsidize projects, but private sector backers like the military and major airlines are also heavily involved. Startups face high costs, and some major players, including Rolls-Royce, have backed out. However, once scalable, mass production of electric aircraft could reduce maintenance and operating costs, potentially making them more affordable for airlines and consumers alike.
Far-Out Timeline: Despite progress, widespread electric aviation is still on the distant horizon. Small electric aircraft are already flying, and planes with up to 19 seats are expected by the late 2020s. Hybrid-electric regional aircraft may follow in the 2030s, with larger models arriving post-2040. While Norway aims to electrify all domestic flights by 2040, it will take time for the technology to normalize and for infrastructure and regulatory frameworks to catch up.
New Safety & Maintenance Considerations: Electric aircraft introduce new safety and maintenance challenges, particularly related to lithium-ion batteries. These batteries, while common in electric vehicles, do not yet meet the rigorous safety standards required for commercial aviation due to their flammability. Lithium-ion batteries have caused numerous fire and fume incidents in other applications, raising significant concerns for their use in aircraft. Currently, safety measures include isolating cells and venting any gas release, but these solutions add substantial weight—about 15% for unpiloted and 30-40% for piloted aircraft. Moreover, practical batteries must offer long cycle life, reliable power, fast charging, and operate safely across a wide temperature range. The FAA has yet to determine specific energy reserve requirements for eVTOL aircraft, though current regulations mandate 30 to 45 minutes of reserve energy for commercial planes in VFR conditions.
Electric Aviation Opportunities
Environmental Impact: Electric aircraft promise reductions in non-CO2 emissions, as they produce zero NOx, water vapor, or particulate matter, thereby reducing both warming impacts and air quality degradation. However, their effect may be somewhat limited since they will mainly replace lower-altitude flights, where contrail formation is less of an issue. eVTOLs, in particular, offer the advantage of reduced noise pollution, potentially allowing more aircraft operations without disrupting nearby communities. In the single-aisle aircraft segment, even minor efficiency improvements can lead to substantial emissions reductions. Additionally, by handling short-haul flights, electric aircraft could help conserve hydrogen and SAF, which are crucial for longer flights, thus amplifying the overall decarbonization efforts of aviation.
Innovation & Efficiency: The advent of electric aviation pushes the industry toward significant innovation and efficiency improvements. Electric aircraft benefit from fewer moving parts and likely reduced maintenance compared to conventional aircraft. Electric motors are also highly efficient, converting about 70% of the energy used for charging into propulsive power, which is superior to many existing aircraft engines.
Business Aviation will be the Tech Incubator: Business and general aviation are likely to be the first areas where electric aviation makes an impact. Small aircraft, which operate at lower speeds, altitudes, and ranges, are more straightforward to certify. Electric aviation offers a new approach to traditional hub-and-spoke models by enabling a network of decentralized aircraft that can serve small, hard-to-reach communities. This creates a unique opportunity for testing and scaling electric aviation technologies. Short-range eVTOLs could serve as personal air vehicles, air taxis, and cargo carriers, with studies suggesting they offer value even for flights as short as a few minutes.
Potential Regional Airline Boom: Electric aviation holds substantial promise for regions with strong regional markets, such as Norway, India, the Philippines, and Australia, because of their ability to connect communities with much less expensive operating costs than traditional aircraft in this space. In the past these operating costs have limited regional aircraft networks, but electric aviation operations have the potential to revive them. Furthermore, eVTOLs could significantly improve connectivity in densely populated urban areas in the US, such as the LA metro region or linking NYC airports including Newark, JFK, LaGuardia, and Teterboro.
Hybrid Advancement in the Meantime: While aviation industry works towards achieving fully electric flight, hybrid aircraft present a valuable opportunity in the interim. Hybrid designs, particularly for commuter and larger aircraft, not only provide practical ranges and meet reserve requirements but also offer notable fuel savings—around 3-6%—by utilizing electric assist during critical phases like takeoff. This hybrid approach serves as a strategic avenue to advance aviation technology, bridging the gap to full electrification. Additionally, hybrid technology supports retrofitting existing aircraft, with initiatives like Dovetail Electric Aviation's work on the Beechcraft King Air and NUNCATS' development of e-conversion kits for light sport aircraft.
What's Next?
One of the biggest opportunities for electric aviation is in the general aviation market. Smaller aircraft, particularly those powered by leaded fuels, are a prime candidate for electric conversion or replacement. The training market is dominated by smaller general aviation aircraft with training flights typically being no more than 2 people and 1 – 2 hours. These are the perfect missions to be replaced by electric aircraft.
The world’s first fully electric aircraft, the Pipistrel Velis Electro, was certified in the UK in 2022. 4AIR announced in September 2024 that it was sponsoring an Electro at a local flight school outside London to help expose students and general aviation pilots to electric aviation while offering it as a decarbonized training platform.
Recent Breakthroughs
Recent advancements in electric aviation are paving the way for significant industry transformation. NASA is at the forefront, developing solid-state batteries, including a sulfur-selenium prototype that achieves 500 Wh/kg—twice the energy density of standard lithium-ion batteries. These advanced batteries promise greater range and performance. Major EV battery manufacturers, such as CATL, are also expanding into the electric aircraft sector. Companies like Joby and Archer are making strides, aiming to have their four-seat aircraft certified by the FAA by late 2024 and operational by 2025. As previously mentioned, small electric aircraft like the Velis Electro and Bye Aerospace’s eFlyer 2 are now entering the training and general aviation markets. The surge in urban air mobility is evident, with over 100 firms developing short-range eVTOL vehicles.
For a detailed look at the industry's development trajectory, see the National Renewable Energy Laboratory's overview of aircraft electrification progress:
Description: “Table 1 shows the near-term to long-term technology horizons, the potential trajectory of aircraft development including use cases, descriptions of aircraft projected for uses, companies currently developing aircraft for those uses, and their current size”
Source: NREL - Electrification of Aircraft: Challenges, Barriers, and Potential Impacts
Airports and Service Providers Will Play a Pivotal Role
According to the July 2024 International Council on Clean Transportation (ICCT) study, all new aircraft must be net-zero—either zero-emissions or powered by 100% low-carbon SAF—by 2037 for airlines to meet their 2050 climate goals. This urgency highlights the need for airports, FBOs, and service providers to start adapting infrastructure now. As Scott Cutshall, President of Real Estate & Sustainability at Clay Lacy Aviation, notes, “Electricity represents a new type of fuel for aviation.” FBOs can prepare by forming strategic partnerships, such as Clay Lacy’s recent collaboration with Joby. Their presence in key eVTOL launch markets underscores the advantage of early action for future customer demand.
Service providers constructing new facilities should integrate electricity requirements into their planning. Long-term success will depend on early adoption and the ability to adapt to ongoing industry developments. As noted by executives at the recent Airports Council International-North America Conference, “airports that are not actively engaged in adopting advanced technology and the infrastructure to support it will be left behind.” (Aviation Week)
Support Electric Aviation
While fully electric aviation is still on the horizon, now is the critical time to invest in its future. 4AIR’s Aviation Climate Fund offers a unique opportunity for stakeholders to support the advancement of aviation technologies and emissions reduction solutions. This nonprofit fund aims to accelerate innovation by providing grants and investments to universities, research centers, and nonprofits focused on developing next-generation battery technologies and zero-emissions solutions. Contact us to learn more about how to participate.
Sources:
Net zero 2050: new aircraft (iata.org)
The challenges and opportunities of battery-powered flight | Nature
Another Route to All-Electric Flight: Convert Existing Planes | Greentech Media
Reducing aviation emissions over the long and short haul (mckinsey.com)
This is what's keeping electric planes from taking off | MIT Technology Review
➡️ Why Heart Aerospace's electric aircraft is a gamechanger (simpliflying.com)
GAMA Technical Publications – GAMA - EPIC Resource Paper: Interoperability of Electric Charging Infrastructure (Version 1.0, August 2023)
Electrified Aircraft Propulsion (EAP) | Glenn Research Center | NASA
NASA's Breakthrough In Battery Tech Paves Way For Electric Aviation | OilPrice.com
What Can You Expect From Electric Air Taxi Services? | Business Jet Traveler (bjtonline.com)
Airports Have ‘No Choice’ But To Implement New Technologies, ACI Says | Aviation Week Network
Textron Inc - Pipistrel Achieves UK CAA Type Certification For Electric Aircraft, Velis Electro