You may want to hold off from making your own blimps, as i've just read something over on Board Game Geek called "Ballon Busters" that may be off interest to you.....and save you a lot of effort too!!
"A special kit for Wings of War miniatures, featuring a 1/144 scale Caquot - Ae800 balloon miniature (good for every nation at war) and an Allied Nieuport 16 with Le Prieur air-to-air rockets. Two versions of the kit are available, with different color schemes for both the balloon and for the airplane."
It is susposed to be released this year, but as of yet, there is nothing set in stone and the price is currently unknown. The only artwork that is available is pictured below, so it may still be a long way off as we dont even know what the picture on the front of the box is going to be yet.
Hope this helps!