Hydrogen has a volume problem, though. A 1st generation Toyota Mirai contains 5 kg of H2, equivalent to 197 kWh. That would take up 55 m3 at atmospheric pressure which is why the Mirai stores it at ~700 atmospheres. That's still a 78 liter tank. AFAICT 200 kWh of petrol takes up 25 liters, i.e. a third. On top of that the high-pressure tank in the Mirai weighs 87 kg.

Hydrogen also sucks in that it puts you in your own scaling lane. Relying on batteries means EVs, grid storage, et cetera drive down your costs for “free”.

Bertha Benz faced a similar problem in 1888, and had to refuel the Patent-Motorwagen by seeking out pharmacies. Drivers of the steam cars that were popular in France could just pick up a bag of coal from anywhere. (Wait, that doesn't sound right. A bottle of kerosene, then.)

I like the idea of fuel cells, but hydrogen's going to have an image problem as soon as people see the failure mode, if it's just being stored as H2 in compressed tanks. Liquid fossil fuels and electric batteries burn with a gradual flame. Hydrogen suddenly detonates, with a supersonic, shattering shockwave, if it's mishandled.

Even with Cold War money, Lockheed's famed Kelly Johnson couldn't make the logistics work for the CL-400.

If we want clearer aviation then manufacturing synthetic liquid jet fuel (kerosene) is more likely to be viable than hydrogen.