[IW] Zeppelins mean Alternate Timelines. So, how are they made feasible?

[vicky_molokh]

Greetings, all!

Many alternate timelines feature blimps/zeppelins/derigibles as a tech that got more development than here on Earth-0. Examples include Red Alert, TimeShift, IW/AE's Gensback, Arcanum (if you count it as a very alternate earth . . .), War Front Turning Point, and probably many others I don't know (I've seen some mentioned on the fora, but don't remember the names).

But the question is: what do the civilizations of these worlds have that we don't? What would make derigibles feasible?

Thanks in advance!