MARIBOR, Slovenia—H2FLY GmbH, a subsidiary of Joby Aviation Inc., recently completed the world’s first piloted flight of an electric aircraft powered by liquid hydrogen. A state-of-the-art fuel cell system enabled the HY4 plane to make test flights of up to three hours in duration. The twin-fuselage, four-seat aircraft is modified from the Taurus G4 produced by Pipistrel, a subsidiary of Textron Inc.

The successful test flight was part of Project HEAVEN, a European consortium created to demonstrate the feasibility of hydrogen-powered aircraft. Using cryogenically-stored liquid hydrogen instead of gaseous hydrogen enables significantly lower tank weight and volume, leading to longer range.