People are quite happy to cruise at 20 kts on ocean liners to their destination, so why not? I thought airships could be used far more than they are. Slow, yes, but better? I think so (especially from the comfort aspect)! I wondered whether solar powered propulsion for airships could be viable, as all you need to do is *move* a given mass, not lift it as such as the envelope will do that bit. Adjust gas volume to suit loading (do they do this already?).