Do we rebuild our entire fleet of passenger and cargo aircraft and go through a huge capital expense in switching fuels, including all airfield refuelling infrastructure. And also accept less efficient fuels that will push up the cost and inconvenience of travel?

Or do we build synthetic Kerosine plants and keep the entire infrastructure?

You guess...

Oh no, hang on, I forgot, you're so fixated on hydrogen you would insist on the stupid answer.

You can't even see how important trans-oceanic flights are.

Well, OK, you build your hydrogen-powered airplane, and the rest of the world will keep on with business as usual.

And, as usual, I'm sure you'll drop an important constant or get the numbers wrong and your plane will go down in flames. Just make sure that you're on board for the maiden flight, Eh?