I love airships. I have to admit that's why I have a fondness for steampunk. (Air pirates, anyone).
In the real world, though, airships have gotten a bum rap. Ever since the Hindenburg disaster (which we now know would have happened even if the airship had used helium not hydrogen) attempts to design commercial airships have, well, failed. A company tried to set up passenger airship service between Manchester and the Isle of Man, but they went bankrupt before starting operations.
Airships do have advantages. They're slower than jets, but they use a lot less fuel and for many freight operations, where speed is unnecessary, airships or "hybrids"such as the 300 ft ship being constructed by HAV - which can reach 100 mph, airships might be a more economical choice. Smaller airships might be a better option than planes or helicopters for air safaris (they're a lot quieter).
So, what's the obstacle?
Helium. If they used hydrogen, nobody would fly on the things, but we have a shortage of helium, especially in the United States. Although helium is very common in the universe, it's so light it bleeds off into space and the only way to get it is to find helium that's been trapped in the Earth's crust. So, helium has to be mined. And is a limited resource.
Which makes airships suddenly much less attractive than they were. But, ah well, a girl can dream.