I'm far from expert on anything to do with the industry you're targeting or the engineering challenges you might be facing, but the idea sounds so reasonable I'm surprised it's not already a thing.

I'm curious though about the tradeoffs of using the envelope as the tank vs. some other source. I'd assume it introduces more opportunity for leaks, and you have to "oversize" the envelope to stay aloft even after you've used all the fuel necessary for a tour. Is there a situation in which it would make more sense to keep your fuel and H2 separate?

Small feedback: the rotating text on your homepage transitions just a bit too quickly.