Hydrogen planes are not yet a commercial reality. As of October 2026, no hydrogen aircraft has been certified by an aviation authority, and none is carrying fare-paying passengers anywhere in the world. The technology has flown in tests, but the timelines keep slipping, and the measure that is actually cutting aviation emissions in the UK today is a different one: sustainable aviation fuel (SAF).
This guide explains how hydrogen aircraft work, what the UK start-up ZeroAvia and Airbus have achieved so far, why both have scaled back their plans, and where hydrogen fits into UK aviation policy.
How it works
A hydrogen fuel cell aircraft makes power through an electrochemical reaction rather than combustion. Inside the fuel cell, hydrogen stored on board combines with oxygen from the outside air. The reaction produces electricity, which drives electric motors that turn propellers. The reaction itself produces water, not carbon dioxide.
This is the approach taken by ZeroAvia. The company describes its ZA600 as a 600 kW powertrain that uses fuel cells to generate electricity from hydrogen, and says water vapour is the only emission from the engine.
There is a second route: burning hydrogen in a modified gas-turbine engine, much as a jet engine burns kerosene. In November 2022, Rolls-Royce and easyJet announced that they had run a converted Rolls-Royce AE 2100-A regional engine on hydrogen in a ground test at MoD Boscombe Down in Wiltshire. The hydrogen was made with renewable electricity at the European Marine Energy Centre (EMEC) on Eday, Orkney.
Size matters a great deal. Fuel cells suit small, slower propeller aircraft. Long-haul jets would need liquid hydrogen kept at about −250 °C in large tanks. The UK’s government-funded FlyZero study, run by the Aerospace Technology Institute, unveiled a concept for a midsize liquid-hydrogen airliner in December 2021: 279 passengers and a range of up to 5,250 nautical miles. FlyZero said such an aircraft would not be ready for the market before the mid-2030s. It was a design concept, not an aircraft programme.
Real-world examples
ZeroAvia: the UK’s leading start-up
ZeroAvia’s early testing did not go smoothly. On 29 April 2021, its hydrogen-electric test aircraft, a Piper PA-46 Malibu registered G-HYZA, made a forced landing in a field near Cranfield after losing power to both motors. No one was hurt. The Air Accidents Investigation Branch (AAIB) report, published in July 2022, found insufficient ground testing and an ineffective emergency procedure for an inverter lock-out. It also found that loss-of-power events three flights earlier had not been investigated. The AAIB made five safety recommendations.
On 19 January 2023, ZeroAvia flew a 19-seat Dornier 228 from Cotswold Airport for about ten minutes. The aircraft had one conventional turboprop and, on its left wing, a prototype 600 kW hydrogen-electric powertrain using two fuel-cell stacks, compressed hydrogen gas stored in the cabin, and batteries. It was a hybrid test: half the aircraft’s propulsion was conventional, so it was not a hydrogen-only flight. A series of about ten test flights followed, according to trade press.
In November 2025, the UK Civil Aviation Authority (CAA) granted ZeroAvia Design Organisation Approval (DOA). DOA approves the company as an aviation designer. It is not a type certificate, which is the approval an engine or aircraft needs before it can enter commercial service. ZeroAvia says it is the first company seeking to certify a hydrogen-electric powertrain to receive DOA. It has named RVL Aviation as its launch operator, to fly the ZA600 in a Cessna Caravan 208B on UK cargo routes, and says it holds thousands of engine pre-orders, though it has not named the customers. In the United States, the company says the Federal Aviation Administration (FAA) issued formal certification issue papers for the 600 kW system in 2025.
Then came cutbacks. In early 2026, trade press reported that ZeroAvia had laid off about half of its roughly 300 staff. According to those reports, it narrowed its goal to certifying the fuel cell system by 2027, delayed full ZA600 certification by 12 to 24 months, pushed its larger ZA2000 powertrain (for 40 to 80-seat aircraft) to the early 2030s, and planned no test flights for 12 to 18 months.
Airbus ZEROe: the big delay
Airbus originally aimed to have a hydrogen airliner in commercial service by 2035, with a first test flight in 2026. At its Airbus Summit in March 2025, it moved the first flight to the second half of the 2030s. It plans integrated ground testing in Munich in 2027.
Airbus has chosen fuel cells over hydrogen combustion. Its revised concept has four 2 MW electric engines, each with its own fuel cell system, fed from two liquid-hydrogen tanks. It has dropped plans to flight-test a fuel cell powertrain on its A380 testbed.
The reason given, as reported in trade press, was that progress on renewable hydrogen at scale and on aircraft technology had been slower than expected. Reports put the delay at five to ten years, and Airbus has not announced a new service date. The company insists its commitment to hydrogen flight remains “unwavering”.
What the numbers say
The headline figures are modest. The most advanced UK hydrogen powertrain is rated at 600 kW and is aimed at small regional and cargo aircraft such as the Cessna Caravan. Its biggest flight so far, on the Dornier 228, lasted about ten minutes with a conventional engine on the other wing.
The larger aircraft are further away. ZeroAvia’s ZA2000 for 40 to 80-seat aircraft has reportedly slipped to the early 2030s. Airbus’s airliner will not fly before the second half of the 2030s. The FlyZero long-range concept, with its 279 seats and tanks at around −250 °C, remains a study.
By contrast, the UK’s SAF mandate already sets legally binding volumes. In 2025, its first year, it required about 230,000 tonnes of SAF, 2% of UK jet fuel.
Limitations / honest assessment
Hydrogen is only as clean as the way it is made. Most hydrogen today is produced from natural gas, which releases carbon dioxide. For a hydrogen plane to be genuinely low-carbon, the hydrogen has to be made by electrolysis using renewable power, such as offshore wind. Our guide to green hydrogen explains how that works and what the UK plans to use it for.
Hydrogen aircraft are not free of climate impact either. They produce no carbon dioxide in flight, but they still emit water vapour, and its climate effect at cruising altitude is not yet settled. Claims that hydrogen planes leave “no carbon footprint” leave out both the production of the fuel and the water vapour.
Certification is slow and demanding. The AAIB’s findings after the 2021 forced landing showed how gaps in ground testing can turn into problems in the air. A new type of powertrain has to prove itself to regulators before it can carry passengers or cargo commercially, and no hydrogen powertrain has yet done so.
The money is fragile. ZeroAvia’s reported job cuts and Airbus’s delay both point the same way: the companies themselves now expect commercial hydrogen flight to take longer than they first said. Fuel cells look best suited to short regional and cargo routes for the foreseeable future, rather than the long-haul flights of a FlyZero-style airliner.
Hydrogen faces similar hurdles at sea. Our look at hydrogen ferries covers which vessels sail today and what holds them back.
The UK angle
The UK’s main policy for cutting aviation emissions is not hydrogen aircraft but the Sustainable Aviation Fuel Mandate, which came into force on 1 January 2025. It obliges suppliers of jet fuel in the UK to supply a rising share of SAF: 2% in 2025, 10% in 2030 and 22% in 2040, after which it is held at 22% until there is more certainty about supply. The legal basis is the Renewable Transport Fuel Obligations (Sustainable Aviation Fuel) Order 2024.
The mandate also limits how much SAF can come from HEFA, fuel made from used cooking oil and fats. HEFA may make up all of the SAF in 2025 and 2026, but its share is capped at 71% in 2030 and 35% in 2040.
This is where hydrogen comes in sooner. A separate power-to-liquid obligation covers synthetic fuel made using renewable hydrogen, starting at 0.2% of jet fuel in 2028 and rising to 0.5% in 2030 and 3.5% in 2040. In our reading, green hydrogen is likely to matter to UK aviation first as an ingredient in synthetic jet fuel, burned in today’s engines, rather than as a fuel carried on board.
The government has also funded hydrogen aircraft research, notably through the FlyZero study. But for the next decade, the practical changes at UK airports are more likely to involve SAF than hydrogen refuelling.
Frequently asked questions
Are hydrogen planes already flying commercially?
No. As of October 2026, no hydrogen aircraft has been certified by any aviation authority, including the UK CAA and the US FAA, and none is carrying fare-paying passengers. ZeroAvia and Airbus are still at the testing and certification stage.
How do hydrogen fuel cells work in aircraft?
A fuel cell combines hydrogen stored on board with oxygen from the air to make electricity. The electricity powers motors that turn propellers. The reaction produces water rather than carbon dioxide. This differs from burning hydrogen in a modified jet engine, which is the other route being tested.
What is the difference between ZeroAvia and Airbus ZEROe?
ZeroAvia is working on fuel cell powertrains for small regional and cargo aircraft, using compressed hydrogen in its test flights. Airbus is developing a larger airliner using fuel cells and liquid hydrogen. Airbus has pushed its first flight to the second half of the 2030s. ZeroAvia was reported in early 2026 to be aiming to certify its fuel cell system by 2027, with full ZA600 certification delayed.
Is hydrogen the main way the UK is decarbonising aviation?
No. The UK’s main policy is the SAF Mandate, which requires jet fuel suppliers to supply a rising share of sustainable aviation fuel. Green hydrogen matters as an input for synthetic SAF under the mandate’s power-to-liquid obligation.
Why is hydrogen hard to use on long-haul flights?
Long-haul aircraft would need liquid hydrogen kept at about −250 °C in large insulated tanks. The UK’s FlyZero study said even a midsize liquid-hydrogen airliner would not be market-ready before the mid-2030s, and Airbus has delayed its own hydrogen airliner.
What happened to ZeroAvia in 2026?
In early 2026, trade press reported that ZeroAvia had laid off about half of its staff, delayed full certification of its ZA600 powertrain by 12 to 24 months, and planned no test flights for 12 to 18 months.