US-based electric vertical take-off and landing (eVTOL) air taxi company Joby Aviation announced on Thursday that its hydrogen-electric demonstrator air taxi had successfully completed a 523-mile (841.7-km) test flight. The only emission generated by the flight was water (in vapour form). The flight actually took place on June 24, and originated and ended at Marina, in the US state of California.

The flight is believed to be the first forward flight of a VTOL aircraft using liquid hydrogen as its fuel. The aircraft itself was a pre-production example of a battery-electric eVTOL design, also developed by Joby, which was converted to a fuel cell power system, including the installation of a liquid hydrogen fuel tank. The tank has a capacity of 40 kg of liquid hydrogen. The fuel cell powers six electric motors, each driving a proprotor. The aircraft retains some batteries, to provide additional power on take-off and landing. When it landed at the end of this test flight, the aircraft still had 10% of its hydrogen fuel in the tank.

Joby started out with a focus on battery-electric air taxis, for use in urban areas. In 2021, it acquired hydrogen-electric flight company H2FLY, which developed the hydrogen fuel cell system used in this technology demonstrator aircraft. Joby’s conception is that its hydrogen-electric aircraft will operate regionally, complementing its battery-electric urban flight operations.

“Travelling by air is central to human progress, but we need to find ways to make it cleaner,” affirmed Joby founder and CEO JoeBen Bevirt. “With our battery-electric air taxi set to fundamentally change the way we move around cities, we’re excited to now be building a technology stack that could redefine regional travel using hydrogen-electric aircraft. Imagine being able to fly from San Francisco to San Diego, Boston to Baltimore, or Nashville to New Orleans without the need to go to an airport and with no emissions except water. That world is closer than ever, and the progress we’ve made towards certifying the battery-electric version of our aircraft gives us a great head start as we look ahead to making hydrogen-electric flight a reality.”

He highlighted that the “vast majority” of work already done on the design, testing and certification processes for the company’s battery-electric aircraft carried over to the commercialisation of its hydrogen-electric aircraft. It was expected that both types would be able to use the same landing pads, the same operations team, and the same Joby ElevateOS commercial operations support software.

In September last year, the Joby H2FLY team successfully flew a conventional crewed aircraft which was powered by their fuel cell powertrain. Joby plans to start urban air taxi operations next year, using its battery-electric aircraft. Meanwhile, the company also recently acquired autonomous aviation technology company Xwing. Joby is listed on the New York Stock Exchange.