ZeroAvia and the hydrogen fuel cell powertrain that wants to replace jet fuel one regional route at a time

ZeroAvia is building a hydrogen fuel cell powertrain designed to replace conventional turboprop engines on regional aircraft, producing only water vapor as exhaust. The company has already flown both a six-seat Piper Malibu and a nineteen-seat Dornier 228 using hydrogen-electric power, and is targeting commercial operations in the nine-to-nineteen seat category with a 300-nautical-mile range by approximately 2027–2028.

Why Hydrogen Fuel Cells Instead of Batteries or Sustainable Aviation Fuel?

The clean aviation conversation typically focuses on two options: battery-electric and sustainable aviation fuel (SAF). Both have serious limitations. Batteries are heavy, making them impractical for flights beyond roughly 200 miles with meaningful payload. SAF is expensive and still produces combustion emissions.

Hydrogen fuel cells occupy a third path. They offer a significantly better energy-to-weight ratio than lithium-ion batteries, and the only byproduct is water — no carbon dioxide, no nitrogen oxides, no particulates.

How Does a Hydrogen Fuel Cell Powertrain Work?

A hydrogen fuel cell is not a combustion engine. It is an electrochemical device. Hydrogen gas enters one side of a membrane, oxygen from ambient air enters the other, and a chemical reaction generates electricity. That electricity drives an electric motor, which turns the propeller.

There is no burning, no turbine, no hot section. This fundamental difference from conventional engines is what drives ZeroAvia’s projections of 50–80% lower maintenance costs compared to traditional turboprop powerplants, owing to far fewer moving parts. Those figures come from engineering models rather than years of revenue service, but the underlying physics supports the claim.

What Has ZeroAvia Actually Flown?

ZeroAvia has completed two landmark flight tests:

• September 2020: A modified Piper M-class (Malibu) flew on hydrogen fuel cell power out of Cranfield Airport, England — the first hydrogen fuel cell flight of a commercial-class aircraft.
• January 2023: A Dornier 228 twin-engine aircraft flew with its right engine replaced by ZeroAvia’s hydrogen-electric powertrain out of Cotswold Airport, Gloucestershire. The left engine remained conventional.

The Dornier flight proved a critical point: existing airframes can be retrofitted with hydrogen-electric power. There is no need to design an entirely new airplane from scratch.

Why Does Retrofit Matter So Much?

Roughly 25,000 regional and commuter aircraft are in service worldwide, most of them turboprops flying routes under 500 miles. If hydrogen powertrains can be swapped into existing airframes through supplemental type certificates — the same certification pathway Garmin used to install autopilots in legacy aircraft — the industry avoids waiting decades for clean-sheet designs to reach production.

What Routes Could Hydrogen-Electric Aircraft Cover?

ZeroAvia’s ZA600 powertrain produces 600 kilowatts (approximately 800 horsepower), targeting a range of 300 nautical miles. That covers high-frequency short-haul routes like:

• Los Angeles to Las Vegas
• London to Edinburgh
• Seattle to Portland

These routes currently burn jet fuel for roughly 45-minute flights. Hydrogen also offers a scaling advantage over batteries: tanks get lighter as fuel is consumed, just like conventional aircraft. And compressed hydrogen refueling takes minutes, not the 45-minute recharge cycle batteries require.

What Is the Biggest Obstacle to Hydrogen Aviation?

Infrastructure. Hydrogen requires entirely new storage, fueling equipment, and safety protocols at every airport that wants to support it. Unlike SAF, which blends into existing jet fuel and uses existing fuel trucks, hydrogen demands purpose-built ground systems.

ZeroAvia is developing modular fueling stations designed for smaller regional airports and has partnerships with airports in the United Kingdom. But widespread hydrogen availability at airports remains years away.

Where Does the Hydrogen Come From?

This is where the emissions question gets honest. Most hydrogen today is gray hydrogen, produced from natural gas via steam methane reforming, which releases carbon dioxide. The truly zero-emission option is green hydrogen, made by splitting water using renewable electricity.

Green hydrogen currently costs two to three times more than gray hydrogen, and production infrastructure at scale barely exists. The cost trajectory of green hydrogen production is as important to ZeroAvia’s business case as the powertrain engineering itself.

How Is Hydrogen Stored on the Aircraft?

Hydrogen has excellent energy per unit of mass but poor energy per unit of volume — a gallon of jet fuel contains about 3.5 times more energy than a gallon of liquid hydrogen. ZeroAvia uses compressed gaseous hydrogen at high pressure rather than cryogenic liquid, avoiding extreme cold storage challenges but requiring bulky tanks.

During Dornier 228 test flights, tanks occupied cabin space. For commercial operations, the company is developing conformal tank designs that integrate into the fuselage or mount externally. The optimal solution will likely vary by airframe.

What About the Competition?

ZeroAvia is arguably the furthest along in hydrogen aviation. Universal Hydrogen, a Hawthorne, California startup that designed modular hydrogen capsules loaded like cargo containers, ceased operations in June 2024 after running into financial trouble. Its assets were acquired, but the company is gone — a reminder that technical barriers and funding requirements in this space are severe.

ZeroAvia has raised over $150 million from investors including Alaska Airlines, Amazon’s Climate Pledge Fund, British Airways parent IAG, and the United Kingdom government. Alaska Airlines has publicly discussed deploying hydrogen-electric aircraft on shorter Pacific Northwest routes.

What Is the Certification and Timeline Outlook?

ZeroAvia is working with both the FAA and EASA on a supplemental type certificate approach — certifying the powertrain as a modification to existing airframes rather than certifying an entirely new aircraft. This is significantly faster than clean-sheet certification.

Timelines have shifted. The original target was 2025. Current projections point to 2027–2028 for the 9-to-19 seat configuration, with 40-to-80 seat aircraft potentially by the early 2030s. Aviation startup timelines almost always slip; commercial hydrogen-electric passenger flights by 2029 would represent a strong outcome.

What About Safety?

Hydrogen is a small molecule that tends to leak and is flammable across a wide range of concentrations. The aviation industry has a century of experience handling jet fuel at airports but essentially zero operational experience handling hydrogen at scale on an active flight line. Engineering solutions for safe hydrogen handling exist, but the regulatory framework and operational procedures are still being written.

Key Takeaways

• ZeroAvia has flown hydrogen fuel cell power on both single-engine and twin-engine aircraft, proving the technology works in real airframes, not just drones or gliders.
• The retrofit strategy targeting 25,000 existing regional aircraft could dramatically accelerate adoption compared to waiting for clean-sheet designs.
• Green hydrogen infrastructure and cost reduction are the largest barriers — the airplane technology is ahead of the ground systems needed to support it.
• 300 nautical miles of range covers many of the world’s most-flown short-haul routes, where hydrogen-electric power could eventually beat jet fuel on operating cost alone.
• Realistic commercial service is likely by the late 2020s for small regional aircraft, with larger platforms following in the early 2030s.