The UK Civil Aviation Authority has today published findings from its Hydrogen Challenge, alongside a new Hydrogen roadmap marking a step forward in understanding how hydrogen technologies could be safely introduced into UK aviation.

The Hydrogen Challenge brought together the regulator, industry and academia to explore the potential of hydrogen powered aircraft, airport operations and supporting infrastructure, its efficiencies and risks of hydrogen and identify possible gaps in existing regulations.

The Challenge has generated important evidence from 11 different projects that touch on each part of the aviation ecosystem, including airports and engines, and will help the regulator develop the regulatory framework needed to support its safe introduction.

Progress in the Hydrogen Challenge means the regulator has now also released its hydrogen roadmap. This sets out a pathway for the regulator to support scaling hydrogen operations for small aircraft by 2035.

As part of the Challenge, three organisations completed real-world hydrogen demonstrations and trials:

Exeter Airport – using hydrogen powered ground vehicles to complete a zero-carbon aircraft turnaround.
Cranfield Aerospace Solutions – using hydrogen fuel cells to power its Stingray high endurance, high range, high altitude UAS drones.
Rolls Royce, in partnership with easyJet – successfully modified a Pearl 15 engine to run on 100% hydrogen to take-off-thrust and across a fully simulated flight cycle.
Sophie O’Sullivan, Director, Future Safety and Innovation, at the UK Civil Aviation Authority said:

“The development of hydrogen technology in aviation could increase the availability of cleaner aviation fuel for the sector.

“The next decade is going to be transformative for this technology.

“Through the Hydrogen Challenge, we have worked closely with industry to shape the regulations needed to safely introduce new ways to fuel how we fly.”

The Hydrogen Sandbox forms part of the Civil Aviation Authorities Hydrogen Challenge programme aiming to support innovation while ensuring high safety levels.

Exeter Airport working with Cranfield University, TUI and ULEMCo, successfully trialled hydrogen-powered equipment as part of airport ground operations, including supporting a TUI aircraft turnaround in April 2025. Further testing in winter conditions and at night showed hydrogen technology could operate safely in a live airport environment.

Stephen Wiltshire, Managing Director of Exeter Airport which is part of the Regional & City Airports group, said:

“We’re pleased that the work carried out at Exeter Airport has helped inform the CAA’s Hydrogen Challenge and its roadmap for the future.

“Working with partners including TUI, ULEMCo and Cranfield University, we’ve shown how collaboration can generate the practical evidence needed to support innovation.

“We’re proud to be playing an important part in helping shape the future of lower-carbon aviation.”

Cranfield Aerospace Solutions tested a hydrogen fuel-cell power system on its Stingray drone programme, helping identify key safety requirements for future hydrogen-powered aircraft and highlighting the importance of fuel-cell temperature management.

Paul Clarke, Chief Technology Officer at Cranfield Aerospace said:

“The Hydrogen Challenge sandbox provided the ideal forum to accelerate our ideas, establish safe and practical approaches to hydrogen-based solutions, and work with the CAA to navigate certification pathways for the wider aviation community.

“By combining close collaboration with the CAA Hydrogen Challenge sandbox and the robust practices we employ as a Part 21J design organisation, we progressed from concept to the build of a large hydrogen-powered platform in just six months and achieved a successful first flight five months later. It’s a clear demonstration of our ability to bring new technologies through at pace and change the landscape for future platform applications.”

Rolls Royce, working with easyJet, successfully tested an engine powered entirely by hydrogen. Simulating all key stages of a flight, valuable safety and performance data was collected to support the future of hydrogen development in aviation. 

Adam Newman, Chief Engineer, Hydrogen Demonstrator Programme at Rolls Royce said:

“Our programme has given us the clearest insight in the industry into how hydrogen performs in a modern aero gas turbine.

“The pace of delivery has been critical, and the insights gained, many of which are fuel agnostic, will now be applied across our future programmes, including UltraFan®. This strengthens our confidence that the gas turbine will remain at the forefront of sustainable aviation’s future.

“We recognize that introducing technologies like hydrogen propulsion means establishing new standards of safety, often beyond the scope of current rules. Early engagement with regulators, such as our participation in the CAA’s hydrogen challenge sandbox, is critical to delivering these next-generation solutions safely and effectively.”