I think I remember a brief discussion at one of the LUGs about blimps.
Turns out it's actually a dirigible (hard structure with bags of helium) instead of a blimp (large bag that must be inflated to maintain it's shape).
I wonder how many fender benders there were along Hwy 101 when that thing took off. Airships just don't look right up in the air, they move too slow.