Sure, but how will they not explode?
So, remember we mentioned helium earlier? Not only is helium environmentally friendly, but it also, importantly, does not catch fire. The Hindenberg and other airships of the time were actually filled with hydrogen—a famously flammable gas. It was used back then because it was cheap and easy to obtain. Helium, however, is expensive and difficult to come by. But it won’t explode.