Making hydrogen work for intercontinental air travel is an absolutely massive engineering challenge with (as of now) horrible economics. Pure hydrogen is hard t

Making hydrogen work for intercontinental air travel is an absolutely massive engineering challenge with (as of now) horrible economics. Pure hydrogen is hard to store as it corrodes metal, bringing enough of it on a plane to be able to cross the Pacific in a reliable and cost effective manner stretches the limits of physics. Making the unit economics work with green hydrogen is again several times more difficult. We should not be handwavy about replacing global-scale, cheap and reliable systems like long-distance air travel. This is a multi-decade undertaking if we are pushing hard and get lucky.