Edit--
I'll remove foot from mouth later--I now see that aluminum AND iron oxide were in the "dope" on the Hindenberg. But thermite is a precise, intimate mixture of aluminum and ferric oxide.
Danny is essentially right.
However, the main component of the "dope" would have been quite flammable on it's own and may have caught fire without the metal additives...Powdered aluminmum was not a good idea, with or without the iron oxide. The hydrogen did burn, but the fire didn't originate with it, and had the shell not contained the aluminum powder the result may have been quite different, and the shell may not have been ignited by a spark. Improper electical grounding has been implicated, and don't forget the thing still had enough diesel to fly to California.
How many hazards can you combine in one craft?
Metalized films on modern aircraft have been shown to be more flammable than previously thought.
