Cryogenic hydrogen is probably out of the question for aviation. It works for rockets only because they continue topping up right up to the start and then it takes only a few minutes until they are out of most of the atmosphere. If there really is a requirement to use alternative fuels in widespread use, it probably has to be power to fuel conversion. Bio fuels are not practical either, as the amount of biomass that has to be used for biofuels would start to interfere with food production very fast.
Pressurized hydrogen could be possible, but requires quite a heavy structure and there will still be quite a bit of hydrogen leakage as it is a simply too small molecule. All in all hydrogen seems like an obvious choice, however, while it has the highest energy density per weight, it has one of the lowest per volume, which in the end is the problem in aviation.