Dragan,
There's some sort of psychological barrier to digigibles. We wanted to bring an advertising blimp to a trade show a few years back. It's made of flame-retardant material and we'd fill it with helium which of course is not flammable. The Fire Marshal rejected the proposal on the grounds that the blimp would be a fire hazard and even mentioned the horror of the Hindenburg as an example of why blimps could not be allowed. True story!
"... They ne'er cared for us
yet: suffer us to famish, and their store-houses
crammed with grain; make edicts for usury, to
support usurers; repeal daily any wholesome act
established against the rich, and provide more
piercing statutes daily, to chain up and restrain
the poor. If the wars eat us not up, they will; and
there's all the love they bear us."
-- Shakespeare: Coriolanus, Act 1, scene 1
