An airship is any powered, steerable aircraft that it is inflated with a gas that is lighter than air. Hydrogen isn't the only gas usable for airships, but it is the only gas that really makes sense. That is because it has good lift to volume, is relatively inexpensive and is common as dirt. Sure there is the odd helium blimp trying to sell us tires, but that is a novelty more than a useful technology. For all practical purposes the death of hydrogen airships has been the death of any major use of airships at all. Once people had great expectations of airships. Now when most people think about airships they tend to think of this. Basically the dream is dead, and most people feel that it is a good thing. As someone who enjoys questioning common conventions like this I've spent some time thing about weather or not I think it really is a good thing. In the end I'm not sure it is. That is because hydrogen makes for energy efficient air travel. For most aircraft keeping them in the air requires constant energy, but airships don't need that thus making them more efficient. More efficient air travel seems like a really big boon to me. Now I'm sure that there are people right now thinking that the danger hydrogen airships posses renders all other arguments for them a moot point, but I have a few counter argument in regards to this. 1. Things are much different now then when the Hindenburg was a thing. People of the modern world have much better abilities engineer things to be safe, and effective. 2. People don't need to be exposed to the danger. Vehicles can be automated now, and the airships can be used to transport things other than people. Just think of all that shipping taking place over the oceans. The hydrogen airships could be automated to do that as well. The cost of the hydrogen needed to lift a ton isn't very high, plus there is the added bonus that airships wont need to rely on ports and the ocean can't catch fire if there is an accident. If hydrogen airships prove safe, and people become more accept of them, maybe later automated hydrogen airships could be used inland and/or even to deliver packages direct to peoples houses saving the huge amounts of fuel used by delivery trucks. Another thing to consider is the possibility of solar powered airships. There is a great deal of space that on airships that could be covered by solar panels, and hydrogen airships wont have the same issues with weight that traditional aircraft have. 3. Danger is relative. People often talk about danger of one thing without thinking of the bigger picture. Any major endeavor done by people involves some danger, but to be fair you have to compare that to the costs, and dangers, of the alternatives. For example what is the danger to the world of continue to burn huge amount of fossil fuels? At any rate those are my thoughts on the topic at this time. I'd like to read other people's thoughts on the matter.