In the 1930s Zeppelins used hydrogen as the lighter-than-air gas to fill the envelope and give the ship buoyancy.

What kind of gas is used today?
Is it still as flammable as the Hydrogen from airships of the 1930s?

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    $\begingroup$ Helium. This is a trivial topic. Try using the Wikipedia before asking obvious questions. $\endgroup$ Nov 21, 2014 at 6:33
  • $\begingroup$ inflammable mean flammable? $\endgroup$
    – Jamiec
    Nov 21, 2014 at 10:22
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    $\begingroup$ @TylerDurden Not just helium - as ratchet freak pointed out there are airships that use hot air. $\endgroup$
    – voretaq7
    Nov 21, 2014 at 14:19
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    $\begingroup$ @voretaq7 The OP specifically asked about "lighter-than-air gas". I presumed he was talking about substances not including air based on that. $\endgroup$ Nov 21, 2014 at 15:20

1 Answer 1


There are only 2 lifting gasses that are lighter than air and practical for airships;

  1. helium: this is a noble gas which means it's inert. Safest option all around except that US has a monopoly on the production of it. That is also the reason Zeppelins didn't use it because of an embargo the US had at the time against the Germans.

  2. hydrogen: even more buoyant than helium but flammable. It is however easier to get by running a current through water or dropping some metals in an acid.

The third option for providing buoyancy is heated air, this requires a heat source to counteract the loss of heat over time.

  • 2
    $\begingroup$ In addition to the above, the current Zeppelin NT uses Helium - as probably do all (or almost all?) the currently flying commercial airships. See also Why the world is running out of helium $\endgroup$ Nov 21, 2014 at 11:48
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    $\begingroup$ Only two gases which are lighter than air and suitable for airships? You seem to miss Ammonia, Methane or Neon - all of which are possible, although potentially impractical. Methane is combustable, Neon is very rare, Ammonia isn't particularly efficient being not much lighter than air - but those aren't necessarily showstoppers, since Helium is also very rare (in terms of practical availability) and hydrogen is combustible $\endgroup$
    – Jon Story
    Nov 21, 2014 at 11:53
  • $\begingroup$ @JonStory they are also much less buoyant than helium and hydrogen, so you would need much larger bags for the same amount of lift $\endgroup$ Nov 21, 2014 at 11:58
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    $\begingroup$ Indeed, but you make it sound like those are the only two usable gases - perhaps the first sentence would be better as "There are only two gases that are both lighter than air, and practical for use in an airship", avoiding the implication that they are the the only ones suitable BECAUSE they're the only ones lighter than air $\endgroup$
    – Jon Story
    Nov 21, 2014 at 12:00
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    $\begingroup$ he did say 'practical' not 'usable'. $\endgroup$
    – rbp
    Nov 21, 2014 at 14:26

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