Plasticell Zeppelin Model
Plasticells are simply made. You take a balloon that has already been inflated, then spray the outside surface with hot plastic using a nozzle, expelled with a connected nitrogen gas tank. This plastic hardens and conforms to the material, as well as slightly expanding. After enough has been applied, you now have an area that can be depressurized, creating a lightweight cell for zeppelins to use. After that, the Plasticells go into a Zeppelin.
The Zepplin, meanwhile, has undergone a bit of a change. Plastic is formed into the bars and structure, mixed with steel as needed to hold the gondola sections. The Plastic is lightwieght, and has the normal skin stretched over it, before light layers of plastic is applied to the skin through spraying evenly. This ensures that the structure will not be popped by bullets, and robs any that do hit of quite a bit of force, which means taking it down is no longer so easy. The Skin at this point is merely a decoration, no longer needed as the plastic has merged with the structure itself, and is self-supporting.
After that, we just need to do the piping and enginework as normal. This means the new Plasticell Zeppelin can carry more than before, and is next to impssoible to take down with bullets alone. Being able to repair holes mid-flight in the shell is also a plus.
The only real thing we need is the sprayer for now, a tank of hot plastic that is expelled with nitrogen through a pipe nozzle. Though we do need to replace the pipe nozzle part somewhat often, it's made of plastic anyway.