Hello,
it was "Karl" in the film, but in reality there was never a "cloud car" jettisoned from a Zeppelin with its occupant in it, as far as i know. This is fiction from the film "Hell's Angels" made by H. Hughes, as well as the crew "leaving" the ship through the bomb doors .. airship crews indeed were disciplined specialists, but it was neither demanded not done.
I am not so sure about the second story posted by Kees though, but will look for it, or its credibility
. One of the first Zeppelins above England laid a track of jettisoned material which only had to be followed to finally find the stranded wreck at the track's end.
If it happened it must have been an army airship early in the war - the cloud cars were only used by the german army airships, the naval ones tried this once in an experiment, but were not impressed. Cloud cars were a welcomed opportunity by the crew, to smoke a cigarette, which was certainly forbidden aboard the Zeppelins.
Greetings,
Catfish