The avid self-promoters among the companies loudly proclaiming their intention to transform air transportation with electric-powered VTOL aircraft have each done a good job of giving the impression that theirs is the fastest track to progress. But what does this mean for operators and business models unwilling to be constrained by the range and payloads of battery technology, or who are not wedded to vertical lift?
In tandem with the eVTOL crowd, there are multiple promising programs focused on what can be achieved with various hybrid-electric propulsion options on fixed-wing aircraft. Among the anticipated advantages claimed by those taking this track are that the FAA and other regulators could see less technology risk in this approach, clearing the way to type certification under existing rules, rather than new requirements on which the ink does not yet seem to be dry.
In the business aviation mainstream, manufacturers have so far given little indication of what technology they have up their sleeves to shake a dependence on fossil fuels that transcends a switch to sustainable aviation fuel. However, Bombardier’s promising EcoJet program could bear fruit in this regard. So too could Daher’s work with Airbus and Safran on the EcoPulse hybrid-electric propulsion demonstrator based on a TBM 900 aircraft.
At Manassas Regional Airport in Virginia, Electra is now flight testing a two-seat technology demonstrator to lay the groundwork for the nine-passenger hybrid-electric STOL aircraft it aims to certify under the FAA’s Part 23 rules in 2028. According to founder and CEO John Langford, the company is looking to fill an opening for air travel to replace cars for trips of between 50 and 500 miles.
Electra’s secret sauce is the ability to operate from strips of around 300 feet in length, including sites in urban areas, opening up countless new sub-regional commercial air services. This is based on the company’s take on blown-wing technology (also referred to as blown lift), which taps an aerodynamic effect that increases the flow of air over the wing to generate much slower airspeeds than conventional aircraft.
Electra is working to start flight testing a full-scale prototype of its as-yet-unnamed prototype in 2026. As of January, it said it has provisional sales agreements with around 36 prospective operators covering more than 2,000 of the aircraft.
“Short-haul flights are a small part of [aviation’s] carbon problem, but you have to start somewhere,” Langford told AIN. “Our STOL performance means we are runway independent, and dependence on airports is a limiting factor. Our infrastructure needs are very light, and we’re not constrained by electric charging limits.”
According to Langford, a hybrid-electric STOL aircraft has a two- or three-fold payload advantage over most eVTOL designs. “We can spend that advantage in multiple ways, including lowering recurring and operating costs, and allowing passengers to bring luggage on board,” he explained.
Safran is developing a 600-kilowatt electric propulsion system for Electra. This will include a gas turbine based on the French aerospace group’s Arrano turboshaft engine driving its EngineUs 100 electric motors.
Also looking to exploit the advantages of blown-wing architecture is California-based start-up Odys Aviation, which is working on a nine-passenger hybrid-electric model called the Alta. Using an unspecified turbine engine and electric motors, this is expected to have a range of up to 750 miles, or 200 miles on all-electric power, while cruising at 345 mph.
“With our hybrid-electric aircraft, the reserve mission can be operated on fuel, so we can use all the battery power and don’t have to save 30 to 40 percent for the reserve,” Odys co-founder and CEO James Dorris told AIN.
According to Odys, it holds provisional sales agreements with 13 undisclosed airlines across four continents, covering more than 1,200 aircraft. Odys is targeting entry into service in 2028
Textron's Pipistrel Champions Hydrogen-based Approach
Textron subsidiary Pipistrel is taking a different approach by developing both battery-electric and hydrogen-fuel-cell-based hybrid-electric general aviation and regional airline aircraft. In 2020, the Slovenian company was the first to earn an EASA type certificate for an electric aircraft when its two-seat Velis Electro trainer got approval.
Now its engineering team is focused on bringing a piston-powered version of its four-seat Panthera to market by the end of this year with full IFR capability. In the longer term, Pipistrel wants to offer a version in which the Lycoming engine would be replaced by a hydrogen propulsion system, and it sees scope for both models to co-exist in the market.
Working through joint programs such as the European Union-backed Project Heaven and Newborn with partners including H2Fly and Honeywell, Pipistrel has been at the forefront of efforts to make hydrogen-powered aircraft technically and commercially viable. One potential outcome from this work could be a new 20-seat aircraft being developed under the working title Miniliner that is expected to be market-ready by around the end of this decade.
According to Pipistrel’s director of engineering Tine Tomažič, the ability to combine clean hydrogen fuel with the range flexibility of hybrid propulsion will deliver strong potential to open up new regional services. He expects the aircraft to be able to operate from 2,600-foot runways commonly found in small-town airfields that currently have no prospect of commercial air service.
Last year, Pipistrel and H2Fly, which is owned by eVTOL aircraft developer Joby, flew a hydrogen-powered proof-of-concept aircraft called Mahepa. Tomažič told AIN that the objective now is to expand the available power from current levels of “a few hundred horsepower” (or 200 to 300 kilowatts) to at least 1 megawatt. Through projects such as H2 Helios, led by aerostructures specialist Aciturri, work is now being advanced on key pieces of hardware such as hydrogen fuel tanks and how these would be integrated into new airframes.
In Tomažič’s view, work on making hydrogen propulsion a reality has now moved beyond the somewhat fragmented, theoretical approach of recent years. “The work is now coming together,” he commented. “There were something like 20 concepts being considered, but we are now seeing a confluence [of approaches] that make sense technologically, performance-wise, and commercially.”
In June 2023, French start-up Beyond Aero put its marker down by announcing plans for a hydrogen-powered business jet currently called the BYA-I. It says this could be ready to enter service in 2030, carrying four passengers on trips of just over 900 miles at speeds of 350 mph.
VoltAero is another start-up partnered with Safran for its four- to 12-passenger Cassio family of hybrid-electric commuter/utility aircraft. The French company is also flight-testing a technology demonstrator as it prepares to fly a prototype of the Cassio 330 model this year. This combines the EngineUs motors with a 156-kilowatt Kawasaki engine.
VoltAero intends the aircraft, which will also include the larger Cassio 480 and 600 models, to only use electric power for taxi, takeoff, and landing, while the hybrid engine will power cruise flight to extend range (of up to 800 miles) and recharge the batteries. The company has reported provisional sales commitments totaling 218 aircraft and has previously expressed an interest in launching a fractional ownership offering with partners.
European Eco Politics Drives Change
Also in France, Aura Aero is stepping up work on a 19-passenger regional airliner called ERA, for which it froze the design last year. It is also developing an all-electric trainer called the Integral E, which is yet another application for the Safran EngineUs motors.
The ERA design unveiled in May 2023 now features eight electric motors (up from six in an earlier version), a pair of turbogenerators, and battery packs. With a T-shaped tail and winglets, the aircraft is expected to operate on routes of up to 900 nm, although more typically probably just 200 to 350 nm, from runways as short as 2,600 feet. Aura Aero is targeting a first flight in 2026, leading to type certification in 2028, and has reported letters of intent covering more than 500 aircraft, including up to 150 units as part of an agreement signed with JSX in December.
Increasingly strong political signals in Europe that the days of fossil-fuel-dependent regional air transport could be numbered appear to have spurred several other start-ups into action. Nonetheless, airline range and payload requirements are prompting a crawl-walk-run approach to decarbonization.
In Sweden, Heart Aerospace abandoned plans for an all-electric 19-seat aircraft in favor of a 30-seat hybrid-electric model called the ES-30. This design, which has attracted support from the likes of Air Canada and United Airlines, is expected to operate up to around 500 miles in hybrid mode, or 125 miles with electric power. On February 1, the company announced the completion of a $107 million Series B funding round, taking its total financing to $145 million.
In December, Dutch start-up Maeve Aerospace took a similar step when it traded out previously announced plans for a 44-passenger electric commuter for an 80-seat hybrid electric model. It is aspiring to a longer range of just over 900 miles, with a propulsion system expected to consist of a pair of unspecified turboprops, two electric motors, and 10 battery packs. The company is aiming to complete its design review for the M80 model this year and bring it into service in 2031.
Some pioneers still see potential for all-electric fixed-wing aircraft. Eviation, which first unveiled its nine-passenger Alice design at the June 2019 Paris Air Show, has been operating somewhat below the radar since achieving a first flight in September 2022. It is unclear what progress has been made towards an anticipated Part 23 type certification in 2027, with unconfirmed reports that it may be opting for what would be a second redesign of the model.
In January, the company appointed Andre Stein as its new CEO, bringing with him experience of eVTOL development with Embraer offshoot Eve Air Mobility. Former Gulfstream executive Jeff Hurford has been appointed CFO, perhaps heralding the need for fresh fundraising for a program that, like so many in the electric aviation space, claims to have multiple sales agreements in place.
Beta Technologies, which is making more tangible progress in moving its Alia-250 eVTOL model towards type certification, last year confirmed it will also offer a conventional takeoff and landing version of the six-seat, all-electric design, called the CX300. This will be certified under existing Part 23 rules, with the Vermont-based company targeting first deliveries in 2025, ahead of the anticipated eVTOL approvals under the FAA’s new Part 21.17(b) rules.
For others, the preferred approach is to re-engine existing aircraft, with the Cessna Caravan and DHC-2 Beaver having emerged as popular candidates for a switch to hybrid-electric propulsion. Companies including Ampaire, MagniX, and Surf Air are all working on plans for supplemental type certificate conversions. At the same time, ZeroAvia and Universal Hydrogen are advancing work to switch regional airliners such as the Dash 8 and ATR 42 and 72 to use hydrogen-electric fuel cell powertrains.