Hanneke Weitering is a writer and editor with AIN covering advanced air mobility and new flight technologies. She became an aviation journalist and joined the AIN team in the summer of 2022 after reporting on spaceflight and astronomy for six years at Space.com. After earning a bachelor’s degree in physics from the University of Tennessee, Knoxville, she moved to New York City to pursue a master’s degree in science, health, and environmental reporting at New York University&#039;s Arthur L. Carter Journalism Institute. She is now based in Seattle near Boeing Field and spends her free time exploring nature in the Pacific Northwest.

Science & Technology Editor

Hanneke Weitering

While most eVTOL aircraft developers have committed to either purely battery-electric or hybrid powertrains, Alaka’i Technologies believes that hydrogen fuel cells offer the best solution for sustainable, emissions-free air transportation. The company is developing a four-passenger, hydrogen-powered eVTOL aircraft called Skai that it says will boast an initial range of 200 miles. A subsequent larger version of the aircraft will be able to fly twice as far, Hugh Kelly, head of marketing at Alaka’i, told AIN.
Alaka’i, which unveiled the Skai concept in 2019, has already built three full-scale prototypes of the multicopter vehicle and has been conducting routine hover flight tests for the past few years at its hangar facilities at Minute Man Air Field, a small airport near Boston, where the company has set up a liquid hydrogen fueling station. While Alaka’i isn’t committing to a date for entry into service, the company has begun the FAA type certification process with the submission of its G-1 issue paper. “We expect to be done with G-2 later this year,” Kelly said, “and then we'll do G-3 and G-4 and hopefully be into the full inspections phase and all the testing next year, and that usually is a nine- to 18-month process.”
Kelly explained that Alaka’i chose the hydrogen route because the power-to-weight ratio of lithium-ion batteries greatly restricts the range and payload capacity of an electric aircraft. “The problem is the FAA requires us to have 20 minutes of reserved flight time, and that's very difficult to do with batteries and still maintain any reasonable distance,” he said.&nbsp;
Hydrogen, on the other hand, is one of the most energy-dense fuels available. “Because the energy density is so much greater and the power-to-weight ratio is so much better, we can get that longer range, so we don't need recharging infrastructure every time we stop,” Kelly said. While the <a href="https://www.ainonline.com/aviation-news/air-transport/2023-03-23/united-airlines-and-archer-reveal-first-air-taxi-route-chicago">first eVTOL air taxi routes</a> expected to launch in 2025 entail approximately 10-minute flights between city centers and airports with downtime for charging, the Skai will have a flight duration of up to four hours and can complete multiple trips before needing to refuel.&nbsp;
Although hydrogen fuel cells are more expensive than the off-the-shelf EV battery cells most electric aircraft developers are using, Kelly said the company is “very confident that the benefits from the weight and the longer life cycle will more than pay for that.”&nbsp;Like lithium-ion batteries, hydrogen fuel cells must be replaced periodically, but not as frequently, Kelly explained, adding that 95 percent of the materials in hydrogen fuel cells are recyclable.&nbsp;
Alaka’i anticipates that new hydrogen tax credits proposed by the Biden administration will further reduce the Skai’s operating costs over time. The <a href="https://www.federalregister.gov/documents/2023/12/26/2023-28359/section-45v-credit-for-production-of-clean-hydrogen-section-48a15-election-to-treat-clean-hydrogen">45V Clean Hydrogen Production Tax Credit</a>, established under the Inflation Reduction Act, provides hydrogen producers with a tax credit of up to $3 per kilogram of “green hydrogen”—meaning it’s made via electrolysis using renewable energy sources such as solar and wind. “Our models suggest that we could drop from an hourly operating cost of around $1,100 today down to less than $800 in five to six years,” Kelly said.&nbsp;
For its flight-testing activities in Massachusetts, Alaka’i obtains green hydrogen from a production plant near Niagara Falls in New York, which ships the fuel to Massachusetts in tanker trucks. Refueling the aircraft’s hydrogen fuel cells is “fairly simple,” Kelly said. “We have a fuel port on the vehicle, you plug a hose into it that locks in place, and it takes about 10 minutes to transfer the hydrogen.”&nbsp;
The Skai will initially serve customers in the business aviation and general aviation sectors that require transportation to and from small airports, said Kelly, who called the service “an extension of the private aviation market.” For example, “think of corporate aviation departments who need to transport people to their jets, or aircraft management companies who handle high-net-worth individuals, or fractional ownership,” he said. “This saves a lot in terms of having to relocate jet aircraft, which adds up on the hours that contribute towards maintenance costs.”&nbsp;
Eventually, Kelly said, Alaka’i will likely expand its operations with scheduled passenger services and potentially on-demand and ride-share air taxi services. He expects the flights will initially cost about three times as much per mile as a ground ride-sharing service such as Uber. Alaka’i is also considering an autonomous version of the aircraft that could transport five passengers with no pilot on board, but Kelly said he expects the FAA is at least a decade away from approving such operations.

News and developments about airplanes, helicopters and unmanned air vehicles used in all varieties of operations, including airlines, military, business, commercial, general aviation and private.

Alaka’i Makes the Case for Hydrogen-powered eVTOL Aircraft

Hydrogen fuel cells power the Skai eVTOL

Alaka’i Technologies has been flight testing a four-passenger eVTOL aircraft powered by hydrogen fuel cells.

2024 Corporate Aviation Leadership Summit

David Donald

Essential news and analysis on the defense aerospace business. Your trusted source for new and ongoing programs and requirements in military aircraft (manned and unmanned), engines, avionics, weapons and associated systems, including ground-based air defense.

At the end of last year China revealed that it had not one, but two, advanced new warplane prototypes in flight test

China’s Fighter Surprise Challenges Western Defense Programs

Sarah Rose

News and issues concerning general aviation, specifically airplanes and helicopters powered by piston and alternative engines (i.e., non-turbine powered aircraft). Subjects include aircraft, engines, personnel, acquisitions, accidents, safety, security and training.

Headlines from the Paris Air Show

Paris News Briefs:  June 15, 2025

Charles Alcock

News and developments about aircraft engines, including turbofan, turboprop, turboshaft and piston.

News about environmental issues relating to aircraft operations, including noise issues, emissisions, and regulations. See Fuel for biofuel.

News and issues relating to international air transport and cargo carriers, national airlines and regional airlines, including aircraft, engines, personnel, acquisitions, accidents, safety, security and training.

Beta's Alia CX300 aircraft is expected to turn heads with its flying display

Electric Aircraft Vie for Attention at Paris Air Show

News about simulators and training procedures, as well as workforce.

In late May, Hungarian pilots completed training with Aero Vodochody

Hungary’s Air Force Set To Receive L-39 Skyfox Trainers

News about bills, laws, regulations and other governmental decisions affecting aviation and aerospace. Topics include FAA re-authorizations, taxes on fuel and aviation activities, environmental legislation, ICAO decisions, governmental mediation of labor conflicts and World Trade Organization disputes and decisions.

News and issues relating to the aerospace industry that are related to the science, engineering and business of flight in space involving civil, industrial and military applications, and similar topics related to flight in the atmosphere of the Earth that are not covered more directly by other AINonline subject channels. In other words, both astronautical and aeronautical subjects, except for those aeronautical topics that are specifically covered elsewhere on this website.

State representatives at Paris Air Show play down concern over Trump tariffs

American States Seek Foreign Aerospace Investment

The Increment 3 Block 2 upgrade for the P-8 greatly enhances its ASW, ASuW and ISR capabilities

Improved Multirole Poseidon Aircraft Prepares for Service

News and developments about everything that goes into the cabin of an aircraft, from floor coverings to headliners, with a special emphasis on in-flight entertainment, communications and other electronics for passengers. If it is in the cabin of an aircraft, it’s covered here.

More In Aircraft

China’s Fighter Surprise Challenges Western Defense Programs

At the end of last year China revealed that it had not one, but two, advanced new warplane prototypes in flight test

Paris News Briefs: June 15, 2025

Headlines from the Paris Air Show

Electric Aircraft Vie for Attention at Paris Air Show

Beta's Alia CX300 aircraft is expected to turn heads with its flying display

Hungary’s Air Force Set To Receive L-39 Skyfox Trainers

In late May, Hungarian pilots completed training with Aero Vodochody

American States Seek Foreign Aerospace Investment

State representatives at Paris Air Show play down concern over Trump tariffs

Improved Multirole Poseidon Aircraft Prepares for Service

The Increment 3 Block 2 upgrade for the P-8 greatly enhances its ASW, ASuW and ISR capabilities

Liebherr Highlights Aircraft Systems Innovation

Folding wingtips for Boeing 777X is one of several innovations on display at Paris Air Show

European Defense Budget Rises Could Boost Air Power

Spending is set to accelerate in the coming years

AIN Products

SUBSCRIPTIONS

RESOURCES

ABOUT AIN