Last I checked, hydrogen has 3 times the energy content of gasoline.
How much can you fit into my 12 gallon gas tank?
At what, 20 times the volume?
Plus, for the scientifically illiterate, because you can’t mine/drill for hydrogen on earth, it is effectively an energy storage mechanism, not a source of energy.
Meaning just like your electric car, your hydrogen powered car/jet/whatever is ultimately powered by fossil fuel anyway.