Not that we are making a prediction here, just pencil sketching in a possible route to viability. Andrew Orlowski points out that electric ‘planes, even hydrogen ‘planes, might not really work:

Hydrogen can’t power the green flight revolution

Aviation is an unforgiving battleground – review the physics and reality bites very quickly

We’re willing to agree for the point of argument. But only up to the point that the suggestion is that the hydrogen go up with the ‘plane.

Imagine that we do get to cheap, green, hydrogen. No, just imagine. If solar gets cheap enough then this will indeed be possible. Really cheap electricity from solar power, electrolyse water and there we are, cheap, green, hydrogen. What then?

Fischer–Tropsch

We know how to do this. If we’ve hydrogen - and we know there’s no great shortage of CO or CO2 around, that’s rather our problem - then we can make complex hydrocarbons. Like, say, aviation or jet fuel. At which point we can use the entire global installed base of ‘planes and technology.

You’re right, this isn’t terribly efficient as a pathway but if that solar power at the start of it is cheap enough then it does all work. We have seen estimates (pretty sketchy ones to be fair) indicating that if that solar panel derived electricity is 2 to 4 cents per kWh then the resultant jet fuel is price competitive with the more traditionally derived fossil oil stuff. We’ve also seen talk that certain bids in Abu Dhabi for solar installation have prices of 1.8 cents per kWh.

We don’t guarantee those numbers but they’re usefully indicative we feel.

This would make the future of air travel very like the present of air travel. Which we think would be nice for folk do seem to like their air travel. The only people who would be unhappy about this are those using climate change as an excuse to stop the proletarians enjoying that mobility which is properly the preserve of the antinomian classes. And of course there are just none of those around at all, are there?