I don't think this is an issue. It's a 1% problem.

Most of the population of the world lives on 2 contiguous land masses. Flights to bridge the masses is fine but would represent a small fraction of the transport needed.

Rail doesn't have to solve all problems. It's a good solution to most problems.

But back to the blimp proposals, I can't see how a blimp would be a better option vs a boat. (Traditional flight is probably better than either).