Hydrogen is markedly more energy-dense than kerosene, by unit weight. It takes up more room, and in particular more room than fits in wings. So it needs a diffe

Hydrogen is markedly more energy-dense than kerosene, by unit weight. It takes up more room, and in particular more room than fits in wings. So it needs a different tankage scheme. Underwing nacelles seem practical. Hydrogen works fine in jet engines, but also in fuel cells driving electric turbines. Once aircraft using hydrogen enter a route, kerosene craft become unable to compete, because the huge reduction in fuel weight translates to substantially increased paying-cargo capacity. It will depend on infrastructural changes, in particular synthesis from grid power and storage at airports, and a cheap renewable-power surplus.