> realistically, a passenger-carrying aircraft would need large cylindrical tanks on the wings for safety reasons, but also with increased drag. Precisely. Any

> realistically, a passenger-carrying aircraft would need large cylindrical tanks on the wings for safety reasons, but also with increased drag. Precisely. Any weight savings of energy density per wt of hydrogen are offset by the poor energy/volume, plus the need for cylindrical tanks for stress reasons. Wing fuel tanks are roughly wing-shaped, meaning no increase to cross section. Hydrogen would require sets of cylinders, which add walls which add weight yet don't directly aid the engineering constraints, or exist outside the current flight envelope, adding drag. Maybe some big advancement in construction methods could allow synergy of hydrogen tanks walls with aircraft structure, but you are still stuck with 1/3rd volumetric density of energy, meaning larger cross section, more drag, and more fuel usage. https://en.m.wikipedia.org/wiki/Energy_density#/media/File%3AEnergy_density.svg https://en.m.wikipedia.org/wiki/Energy_density#/media/File%3...