ZeroAvia and the hydrogen-electric powertrain that could kill kerosene on regional routes

ZeroAvia is building a hydrogen fuel cell powertrain designed to replace conventional turbine engines on regional aircraft, targeting nine- to nineteen-seat turboprops first and scaling to larger regional planes by the early 2030s. The core physics are sound — hydrogen stores roughly three times the energy of jet fuel by mass and fuel cells convert it at double the efficiency of turbines — but the path to commercial service faces serious infrastructure and scaling challenges that no amount of engineering alone can solve.

What Is ZeroAvia Actually Building?

Founded in 2017 by Val Miftakhov, a physicist and pilot with a background in electric vehicle charging, ZeroAvia’s strategy is deliberately narrow: build a drop-in replacement powertrain, not a new airplane. The company takes an existing certified airframe, removes the turbine engine, and installs a hydrogen fuel cell system driving electric motors.

This distinction matters enormously. Certifying a brand-new aircraft design takes a decade and roughly a billion dollars. Certifying a new powerplant for an existing type is still difficult, but it is a fundamentally shorter regulatory path.

How Does a Hydrogen Fuel Cell Powertrain Work?

Hydrogen stored onboard — either as compressed gas or eventually as liquid hydrogen — feeds into a proton exchange membrane (PEM) fuel cell. This is the same basic chemistry that powered the Gemini spacecraft in the 1960s.

Inside the fuel cell, hydrogen meets oxygen from ambient air and produces two outputs: electricity and water. No combustion. No CO₂. No nitrogen oxides. No soot. The electricity drives electric motors connected to propellers. Water vapor exits as exhaust.

Why Hydrogen Instead of Batteries?

Batteries hit a hard limit called specific energy. Today’s best lithium-ion cells store about 250 watt-hours per kilogram. Jet fuel stores roughly 12,000 Wh/kg — a 48-to-1 ratio. Even accounting for the thermodynamic inefficiency of turbine engines, which waste about two-thirds of that energy as heat, kerosene still wins by a factor of roughly 15 on usable energy per unit weight. That is why battery-electric works for a two-seat trainer flying 40-minute hops but falls apart for anything carrying 20 passengers over 300 miles.

Hydrogen changes the math. Compressed hydrogen gas at 700 bar stores about 33,000 Wh/kg — almost three times the energy density of jet fuel by mass. Fuel cells convert that energy at 50–60% efficiency, roughly double what a turbine achieves. On paper, hydrogen fuel cell propulsion is competitive with kerosene on an energy-per-kilogram basis for regional missions.

What’s the Catch? Volume, Not Weight

The limitation is energy per liter, not energy per kilogram. Hydrogen is the lightest element in the universe, and even compressed to 700 bar, it occupies four to five times the volume of jet fuel for equivalent energy content. The tanks are enormous.

On ZeroAvia’s Dornier 228 testbed, hydrogen tanks eat into cabin space, cargo volume, or both. For a 19-seat regional turboprop, this means redesigning significant fuselage sections or mounting tanks externally.

Liquid hydrogen partially solves the volume problem because it is much denser than compressed gas, but it must be stored at −253°C — just 20 degrees above absolute zero. The cryogenic tank technology, insulation, and boil-off management represent an entire engineering discipline.

Where Is ZeroAvia’s Flight Test Program Today?

• September 2020: Flew a modified Piper M-class (six-seat aircraft) on hydrogen fuel cell power at Cranfield Airport, England — the largest hydrogen fuel cell aircraft to fly at that time.
• January 2023: Flew the left engine of a Dornier 228 (19-seat twin-engine aircraft) on hydrogen fuel cell power, with the right engine running on conventional fuel — the first hydrogen-electric powertrain flight on a commercial-size aircraft.

Both are genuine milestones. But the Dornier flew with one hydrogen engine and one kerosene engine. The hydrogen powertrain produced about 600 kW. A full replacement powertrain for that aircraft needs approximately 1.5 MW. Scaling from 600 kW to 1.5 MW while maintaining viable weight is not simply a matter of adding more cells.

Thermal management becomes a different problem at that power level. At 55% fuel cell efficiency, the remaining 45% exits as heat. At 1.5 MW, that is 675 kW of waste heat requiring radiators, coolant loops, and airflow management — all adding weight and drag.

What’s the Realistic Timeline?

ZeroAvia originally projected a certified 600 kW powertrain for 9- to 19-seat aircraft by 2025. That target has slipped. Current guidance points to:

• ZA600 powertrain (9–19 seat aircraft): certification in the 2027–2028 window
• ZA2000 powertrain (40–80 seat regional aircraft, 2–5 MW): early 2030s

In aviation development, timeline slippage is the norm. But every year of delay is a year that sustainable aviation fuel gains ground, battery energy density improves incrementally, and airlines lock in decarbonization strategies around other solutions.

The Infrastructure Problem Nobody Talks About Enough

Today there is essentially zero hydrogen refueling infrastructure at airports. Jet fuel infrastructure took 80 years to build — fuel farms, hydrant systems, fuel trucks, quality control labs, and supply chains stretching back to refineries.

Hydrogen needs its own parallel system:

• On-site electrolysis using renewable electricity, or truck/pipeline delivery of compressed or liquid hydrogen
• High-pressure dispensing equipment
• New safety protocols (hydrogen is flammable across a much wider concentration range than kerosene and burns with an invisible flame)
• Trained ground crews and updated airport fire codes

ZeroAvia has partnered with airports including Rotterdam The Hague and Edmonton International in Canada to develop hydrogen refueling capabilities, with UK government funding through the Aerospace Technology Institute. But building infrastructure for even a few launch airports is a multi-year, multi-hundred-million-dollar effort.

The chicken-and-egg problem is stark: airlines will not buy hydrogen aircraft until fuel is available at their routes’ airports, and airports will not invest in hydrogen infrastructure until airlines commit to hydrogen aircraft. This infrastructure gap is arguably a bigger barrier than the powertrain engineering itself.

Who Else Is Working on Hydrogen Aviation?

• Universal Hydrogen (founded 2020) developed modular hydrogen capsules loadable like cargo containers using existing ground equipment — a clever infrastructure workaround. The company ceased operations in 2024 due to financial trouble, a cautionary data point for the sector.
• Airbus ZEROe targets hydrogen-powered commercial aircraft by 2035, but as a clean-sheet design, not a retrofit. Airbus timelines for new programs are measured in decades.
• H2FLY (Germany) flew a liquid hydrogen fuel cell aircraft in 2023 and has since been acquired by Joby Aviation.

The Competitive Question: Why Not Just Use Sustainable Aviation Fuel?

If sustainable aviation fuel (SAF) can be produced at scale and blended into existing jet fuel at increasing percentages — using infrastructure that already exists at every airport on the planet — why would an airline accept the cost and complexity of hydrogen?

The answer has to be one or both of: hydrogen is ultimately cheaper per seat-mile when carbon costs are factored in, or regulatory mandates force the transition. As of mid-2026, neither condition is clearly met.

Key Takeaways

• The physics works. Hydrogen fuel cells produce enough energy at low enough weight to theoretically power regional aircraft, proven at small scale with real flight tests.
• The engineering is hard but solvable. Scaling from a 600 kW demonstrator to a 1.5 MW certified production powertrain — with manageable thermal loads and weight — remains the core technical challenge.
• Infrastructure is the hidden wall. Airport hydrogen refueling capability is essentially nonexistent and will take years and hundreds of millions of dollars to build, even for a handful of routes.
• Timeline is real but long. Commercial hydrogen-electric regional flights are unlikely before 2030, with the early 2030s more realistic for limited service.
• ZeroAvia has real credibility. Multiple successful flight tests on real aircraft put them ahead of most aerospace startups, but closing the gap to a certified production powertrain will be the definitive test.