Picture a turboprop climb-out over the Scottish Highlands — same crisp view through the oval window, same gentle vibration through the airframe — except the only thing coming out of the exhaust is water vapour. No kerosene burn. No carbon. Just a wisp of steam dissipating into cold air above the glens. That’s the promise sitting at the heart of hydrogen fuel cell aviation, and right now it’s closer to reality than most people realise.
The conversation around sustainable flight tends to get dominated by sustainable aviation fuel, which makes sense — SAF works in existing engines, existing aircraft, existing infrastructure. But SAF is still a combustion story. Burn something, get thrust, accept some byproduct. Hydrogen fuel cells are a fundamentally different proposition. You’re combining hydrogen and oxygen electrochemically, generating electricity to drive motors, and the only exhaust product is H₂O. It’s not an incremental improvement on the jet age. It’s a different philosophy entirely.
So why aren’t we flying on fuel cells already? The honest answer involves physics and practicality in roughly equal measure. Hydrogen has extraordinary energy density by weight — better than kerosene, which sounds wonderful — but its volumetric density is terrible. A given volume of liquid hydrogen contains far less energy than the same volume of jet fuel. That means tanks need to be large, which means airframe redesigns, which means you can’t simply retrofit a fuel cell system into a regional turboprop and call it done. The aircraft has to be conceived around the fuel from the beginning.
That’s exactly what a handful of serious programmes are attempting. ZeroAvia has been perhaps the most visible, having tested hydrogen-electric powertrains in progressively larger testbed aircraft and working toward certification for genuine commercial operations on shorter regional routes. Universal Hydrogen took a modular capsule approach, imagining hydrogen delivered in standardised pods that slide into the fuselage — an elegant attempt to sidestep the infrastructure problem by making the fuel itself portable. The specific timelines and commercial outcomes of these programmes remain genuinely uncertain, as they do for any emerging technology, but the engineering work is real, the test flights have happened, and regulators are actively building frameworks to accommodate it.
What excites me most about the fuel cell path, specifically for regional aviation, is that it actually suits the mission. Short-haul routes — say, under 500 kilometres — are where range limitations bite least and where the stop-start nature of operations makes the efficiency characteristics of electric motors genuinely attractive. A 19-seat or 40-seat regional aircraft connecting island communities, mountain airports, or thin-margin rural routes doesn’t need transatlantic range. It needs reliability, low operating cost, and increasingly, a credible emissions story for regulators and passengers alike. Fuel cells could deliver all three, assuming the infrastructure question gets solved — and solving infrastructure is an engineering and logistics challenge, not a physics impossibility.
There’s something almost poetic about the fact that the humble turboprop — workhorse of commuter aviation, beloved of avgeeks for its exposed spinning blades and raw mechanical honesty — might be the category that leads aviation’s hydrogen transition. Not the flagship widebody. Not the headline supersonic jet. The unglamorous regional hop.
Certification, hydrogen production at scale, airport storage systems, cold chain logistics for liquid hydrogen — none of that is trivial, and nobody serious is pretending the path is straight. But the physics works, the engineering is advancing, and the motivation has never been stronger. One day, that climb-out over the Highlands really will leave nothing behind but water. The view will be exactly the same. Everything else will have changed.