User blog comment:Thethirdpathcometh/So many questions.../@comment-5522245-20120927045435/@comment-121.79.199.85-20120927054425

In reality, Zeppelins are inflated with gas, which is highly flammable. However, the Bloon Empire have a much different, unique gas for their MOABs, as well as a sheet of metal between the unique gas and the outer layer of the MOAB, which prevents many projectiles from getting through easilly. BFBs are similar, but have much thicker, tougher, and larger sheets of metal, and their engines are powered by Ion gas. ZOMGs, however, I have been unable to study - the last time I tried, it destroyed the test chamber I had put it in.