The world’s first piloted flight of an electric aircraft powered by liquid hydrogen has taken place.

H2FLY, the Stuttgart, Germany-based developer of hydrogen-electric powertrain systems for aircraft, today (7 Sep) announced it has successfully completed several trips.

The H2FLY team say they have carried out four flights from Maribor, Slovenia, powered by liquid hydrogen as part of its flight test campaign, including one flight that lasted for over three hours.

They believe the flights lay the foundation for long-range, emissions-free flight, with liquid hydrogen doubling the range of the HY4 aircraft to 1,500km, compared to using gaseous hydrogen.

The flights were completed with H2FLY’s piloted HY4 demonstrator aircraft, fitted with a hydrogen-electric fuel cell propulsion system and cryogenically stored liquid hydrogen that powered the aircraft.

Compared with pressurised gaseous hydrogen storage (GH2), the use of liquified, cryogenic hydrogen (LH2) enables significantly lower tank weights and volume, therefore leading to increased aircraft range and useful payload.

The company say: "Results of the test flights indicate that using liquid hydrogen in place of gaseous hydrogen will double the maximum range of the HY4 aircraft from 750 km to 1,500 km, marking a critical step towards the delivery of emissions-free, medium- and long-haul commercial flights."

Professor Josef Kallo, co-founder of H2FLY, explains: "This achievement"

marks a watershed moment in the use of hydrogen to power aircraft. Together with our partners, we have demonstrated the viability of liquid hydrogen to support medium and long-range emissions-free flight.

"We are now looking ahead to scaling up our technology for regional aircraft and other applications, beginning the critical mission of decarbonising commercial aviation."

Pierre Crespi, Innovation Director at Air Liquide Advanced Technologies says: "Air Liquide is proud to have designed, manufactured and integrated, together with H2FLY, the liquid hydrogen tank that enabled to power the HY4 aircraft."

"Today’s success demonstrates the full potential of liquid hydrogen for aviation. Liquid hydrogen can be stored onboard and transported. Hydrogen is key to the energy transition and this new step proves that it's already becoming a reality."