ZeroAvia, the Hydrogen-Electric Powertrain, and the Dornier Two Twenty-Eight That Runs on a Fuel Cell and Leaves Behind Water

In early 2023, a 19-seat Dornier 228 commuter turboprop flew in northern England with one of its two engines replaced by a hydrogen-electric powertrain - an electric motor fed by a stack of hydrogen fuel cells, producing nothing but water vapor out the back. It was the largest aircraft to date to fly with a hydrogen fuel cell doing real propulsive work in the air. The technology is real and the physics is sound, but fuel supply, tank weight, and airport infrastructure remain the deciding obstacles between demonstration and industry.

What Is Hydrogen-Electric Propulsion?

There are two completely different ways to extract energy from hydrogen aboard an aircraft, and they are not the same technology.

The first is to burn it. You feed hydrogen into a modified gas turbine or piston engine and combust it much like kerosene. Airbus has studied this path seriously. Hydrogen burns well, but you’re still running a hot combustion engine, and burning anything in air at high temperature produces some nitrogen oxides because the flame cooks the nitrogen in the air.

The second way - the focus here - doesn’t burn the hydrogen at all. You run it through a fuel cell.

A fuel cell behaves like a battery that never runs down as long as you keep feeding it fuel. Hydrogen goes in on one side; ordinary oxygen from the air comes in on the other. A membrane lets the hydrogen give up its electrons, which travel around the outside of the cell to reach the oxygen. That flow of electrons is electricity, routed straight into an electric motor that spins the propeller.

When the hydrogen and oxygen finally recombine, they make water. That’s the entire exhaust: two hydrogen, one oxygen. No combustion, no carbon dioxide, and no nitrogen oxides, because there is no flame - just electricity and water.

Who Is ZeroAvia and Why Does It Matter?

ZeroAvia has pushed hydrogen-electric propulsion further into real aircraft than anyone. It was founded by engineer Val Miftakhov, who had already built and sold an electric-vehicle charging company before turning to aviation. The company operates in California and the United Kingdom.

Its key strategic choice was deliberate: it did not design a brand-new airplane. That’s the trap that has swallowed many clean-aviation startups - falling in love with a radical airframe and spending a decade and a fortune trying to certify a shape the world has never seen. ZeroAvia instead took an already-certified airframe with an existing maintenance network and supply chain, and swapped only the powertrain - proving the hard part, the propulsion, on a known-good aircraft.

ZeroAvia started with a six-seat Piper Malibu-class aircraft flown on hydrogen fuel cells, then moved up to the Dornier 228. In the 2023 flight, the second engine remained conventional as a safety backup - the cautious, sensible way to flight-test something new. It was a real propeller turning in the air, not a lab bench or a computer model.

What Makes Hydrogen Fuel Cells So Promising?

The promise is clean: an aircraft that produces water instead of carbon, fuel that can be made from water and renewable electricity rather than an oil well, and an electric motor driving the propeller with fewer moving parts, less vibration, and potentially lower maintenance than a turbine full of hot spinning stages.

Hydrogen’s biggest advantage is energy density by weight. Pound for pound, hydrogen carries about three times the energy of jet fuel. That single number is what gets engineers dreaming.

Why Isn’t Hydrogen-Electric Flight Everywhere Already?

There are three real obstacles, and none of them are about the airplane itself.

Problem one: hydrogen is terrible by volume. It’s the lightest element in the universe - a gift by weight, a curse by space. To make it dense enough to be useful, you compress it as a gas to 5,000–10,000 psi in heavy reinforced pressure vessels, or you chill it to a liquid. Liquid hydrogen is denser and better for longer range, but it must be kept near -423°F, demanding cryogenic tanks, insulation, and acceptance that some fuel will slowly boil off. Either way, the tanks are heavy and bulky, and much of hydrogen’s weight advantage bleeds back out. The fuel weighs almost nothing; the trunks it travels in weigh a lot.

Problem two: where the hydrogen comes from. Hydrogen is clean at the airplane - but only as clean as the way it was made. Today, most hydrogen on Earth is gray hydrogen, made from natural gas in a process that releases carbon dioxide. Fly a “zero-emission” aircraft on gray hydrogen and you’ve simply moved the carbon from the tailpipe to a factory. The clean version is green hydrogen, made by splitting water with renewable electricity in an electrolyzer. Green hydrogen today is expensive and produced nowhere near aviation scale. Honest verdict: hydrogen aircraft can be zero-emission if and only if an enormous green hydrogen supply chain is built first. That’s the main event, not a footnote.

Problem three: the airport. Essentially every airport is set up to pump jet fuel and avgas, not to store and dispense liquid hydrogen at scale. That means tanks, trucks, trained crews, safety systems, and regulation - a chicken-and-egg problem. This is why the smart players start small and regional: short island and commuter runs where the same aircraft flies between two or three airports all day, so hydrogen fueling only needs to exist at a handful of locations.

Hydrogen vs. Batteries: Which Wins?

Battery-electric aircraft are flying today. They’re quiet, cheap to operate, and excellent for training and short hops. But batteries are heavy, and a battery weighs the same empty as full - you carry every pound for the entire flight.

A hydrogen aircraft gets lighter as it flies, the way every fuel-burning aircraft does, and hydrogen carries far more energy per pound than any battery we can currently build. For real routes with real distance, hydrogen has a shot at range batteries simply cannot match with today’s chemistry.

The cleanest way to frame the whole landscape: batteries for the short and light, hydrogen fuel cells for the regional middle, and conventional turbines burning sustainable aviation fuel for long-haul jets for a long time yet. These are different tools for different missions, not competitors for one prize.

What’s the Realistic Timeline?

ZeroAvia has real aircraft flying and has been pursuing certification of its smaller powertrain for 19-seat commuters, with a stated goal of entering service in the middle of this decade, and larger powertrains for 40-to-80-seat aircraft later. It has signed agreements with airlines and lessors for hundreds of systems on paper - genuine momentum from a company that has actually put fuel cells in the air.

But certification is a mountain no one has fully climbed with a fuel cell driving a propeller on a passenger aircraft. The FAA and its European counterpart have decades of rules built around combustion engines. High-pressure or cryogenic hydrogen systems, fuel-cell stacks, and high-voltage electrical distribution all have to be proven safe to a standard that took gas turbines half a century to earn.

The risk is real. Universal Hydrogen, which had a clever idea for swappable hydrogen fuel capsules, flew a converted aircraft and then ran out of money and shut down in 2024. Sound engineering does not guarantee a viable business - a company can die waiting for the money, the market, and the fuel supply to arrive at the same time.

Why This Matters for Pilots

If you fly regional turboprops or commuter routes, hydrogen-electric is the propulsion technology most likely to reach your cockpit first - the 19-seat, short-hop, regional-middle segment is exactly where the engineering case is strongest. The milestone worth watching is not another demonstration flight; the concept is already proven. It’s the first paying passenger route flying on certified hydrogen-electric power, day in and day out, refueling with real green hydrogen at a real airport. When such a route runs for a full year without drama, this stops being a promising experiment and becomes an industry. As of August 2026, we’re not there yet - but for the first time, you can see it from here.

Key Takeaways

• A hydrogen fuel cell produces electricity by combining hydrogen and oxygen, driving an electric motor with water vapor as the only exhaust - no combustion, no CO₂, no NOx.
• ZeroAvia flew a 19-seat Dornier 228 on a hydrogen-electric powertrain (one engine) in 2023, the largest aircraft yet to do so, after starting with a six-seat Piper Malibu-class testbed.
• Hydrogen carries ~3× the energy of jet fuel by weight but is poor by volume, requiring heavy high-pressure (5,000–10,000 psi) or cryogenic (-423°F) tanks.
• True zero emissions depend on green hydrogen made with renewable electricity; most hydrogen today is carbon-emitting gray hydrogen.
• The decisive obstacles are fuel sourcing, tank weight, airport infrastructure, and certification - not the aircraft itself - underscored by Universal Hydrogen’s 2024 shutdown.