Jet engines can almost burn anything, that's easy. The Army even ran a main battle tank on peanut butter once (creamy I presume).
The challenges are:
1. Fuel supply/storage infrastructure. That can solved, at great expense
2. Need actual green power to generate the hydrogen, otherwise it's pointless. That can be solved too. Eventually.
3. Finding the volume onboard aircraft to store the H2 fuel. H2 requires a LOT more volume than Jet A. This is the real hard part, going to need a total redesign of longer-range transport aircraft, basically a blended wing-body or even full flying wing. For short regional flights (like really short) you can use current wing and tube designs.
Yes, H2 is lighter (better specific energy) than jet fuel but the energy density is terrible... the extra aircraft structure to provide the storage volume cancels out any weight benefit, and then some.