top of page

World's First Liquid Hydrogen-Powered Flight Marks Milestone in Aviation

8 Sept 2023

German aviation company H2Fly has achieved a significant milestone in hydrogen-powered flight by completing the world's first liquid hydrogen (LH2) powered piloted test flight. The groundbreaking achievement is part of a four-journey campaign utilizing a demonstration aircraft equipped with a fuel cell-powered propulsion system.

Key Highlights:

  1. Extended Flight Duration: H2Fly's piloted HY4 demonstrator aircraft, with cryogenic liquid hydrogen storage and a fuel-cell system, achieved flight durations exceeding three hours. This duration significantly surpasses previous tests conducted by hydrogen aircraft developers ZeroAvia and Universal Hydrogen, which ranged from 15 to 23 minutes.

  2. Range Doubling: The use of liquid hydrogen instead of gaseous hydrogen has the potential to double the HY4 aircraft's maximum range from 750km to an impressive 1,500km. This enhanced range opens up possibilities for medium and long-range emissions-free flight.

  3. Volumetric Energy Density: Liquid hydrogen offers a substantial increase in volumetric energy density compared to compressed hydrogen. A fuel tank containing liquid hydrogen can store two to three times more energy and, consequently, increase the aircraft's range.

  4. Energy Efficiency: While liquefaction of hydrogen does require electricity, it remains an efficient process that enhances the energy density of the stored hydrogen, making it a viable choice for aircraft propulsion.

H2Fly's achievement represents a significant advancement in the utilization of hydrogen as a clean and efficient energy source for aviation. Professor Josef Kallo, co-founder of H2Fly, emphasized the importance of this milestone and the broader implications for decarbonizing commercial aviation.


Both ZeroAvia and Universal Hydrogen, industry leaders in hydrogen-powered aircraft, are also exploring the use of liquid hydrogen in their larger aircraft models. ZeroAvia aims to certify a powertrain for 9-19 seat aircraft using gaseous hydrogen by 2025, while Universal Hydrogen plans to convert its 40-seater aircraft to use liquid hydrogen.


This groundbreaking flight by H2Fly, along with the ongoing efforts of industry pioneers, underscores the growing potential of hydrogen as a clean and sustainable energy source in the aviation sector. As technology continues to advance, hydrogen-powered aircraft may play a pivotal role in reducing emissions and shaping the future of air travel.


In a historic achievement, German aviation company H2Fly has completed the world's first piloted test flight powered by liquid hydrogen (LH2). The breakthrough promises extended flight durations and doubled maximum range, marking a significant step towards decarbonizing commercial aviation.

bottom of page