[JoshTriplett]

> Safety is not an issue for transport.

It's less of an issue. You still don't want a burning hydrogen zeppelin crashing down on a populated area, and unless you've fully automated it you'll still have human crew aboard (though they'll be better trained and equipped to deal with problems).

[andechs]

If it's filled with Hydrogen, it doesn't burn for very long - it would be an explosive burn. The cargo is still aloft in the air though, but that's also a theoretical problem with planes.