Even for non-ground vehicles my understanding is that the future of H2 is very murky: small aircraft have proven some efficiencies with battery electric that H2 cannot match, other than possibly as a generator to top up a large battery and if the large batteries themselves hit certain densities (which seems increasingly likely as BEV car production picks up and economies of scale start to take effect) it won't be worth the weight for an H2 generator and liquid H2 tanks. I've heard at least one scientist flat out state that carrying liquid H2 is about the dumbest efficiency possibility for air travel because if you are going to carry all that H2 anyway at least carry it as a gas and get free ballast from it. The only efficient H2 air travel is exactly the one we've known about for centuries: dirigibles. But we know that's a PR minefield in current popular culture to even suggest. (Which yes, we probably should have more dirigibles for other efficient air travel options.)

If battery densities end up meeting the needs of airplanes they meet the needs of ships easily enough. Plus, there's interesting new research on wind power for ships, which I find is a lovely irony to see ships return to wind power after all these years (though it may look quite different than the classic age of sail with primary propulsion still being electric turboprops).