Hydrogen is "safe"? You better ask the Hindenburgh crew about that!
Maybe you meant to write "helium". Helium is safe alright, but it is also prohibitively expensive to produce. The military, being goverment (i.e. tax-payer) funded, has of course no budget qualms... they do not have a market place to answer to. But for private travel and transport, the zeppelin age is gone. Unless you find a way to produce cheap helium.