The Department of Defense is getting serious about using airships as military transports. The project, called "Walrus" is supposed to have a prototype with a capacity comparable to the C-130 ready for delivery in 2008, and ultimately plans call for a transport capacity comparable to a Navy troop transport ship (i.e. able to carry 1,800 troops and their gear).
1. They are about three times as fast as a typical transport ship, are almost twice as fast as an off road military convoy overland, and are also faster overland than a military convoy travelling by road or rail.
2. They can travel point to point without an airstrip at either end. In contrast, heavy forces must now be loaded onto railroad cars, unloaded from the rail cars and put on ships, transported via ship to a port, be unloaded at port, and driven to their destination.
3. They are truly all terrain vehicles and can't be harmed by IEDs, land mines, traps, destroyed bridges or barricades on roads. Similarly, they can easily traverse jungles and other densely forested roadless areas at full speed.
4. Cutting edge technological advances aren't required to make it work.
5. They are cheaper to operate, and can carry much more cargo, than airplanes or helicopters.
6. The problems that led to the Hindenberg disaster in 1937 are easily overcome. The Hindenberg was filled with hydrogen gas and more importantly its exterior was coated with a jet fuel variant. Modern airships usually have non-flammable helium in them and have fire resistant components.
Obviously, you don't want an airship flying within the line of fire of hostile troops. But, it is an attractive intermediate option between the expensive and low capacity traditional airlift, and the cheap but slow traditional sealift.
Airships also have significant commercial potential, particularly if the military ends up bearing most of the expensive development costs. For example, commercial airships could be an excellent alternative to ferries in island chains, an excellent means of supporting larger communities (or oil exploration efforts) in the Alaskan interior without having to build ecological damaging and expensive roads, and a good intermediate option for shipping time dependent but not overnight urgent mail and airfreight. Airships are already used for tourism, and are particularly attractive in places where it would be expensive and ecologically damaging to build road and/or bridges for tourists. And, of course, it isn't hard to imagine a Walrus airship swooping down over a pier in St. Bernard Parish, Lousiana that I heard about on NPR this morning with 1,500 people stranded and awaiting a sea rescue, and carrying them all away directly to safety dozens of miles away in a single trip.