Zeppelins were huge airships invented by humans in the 20th century. They were used as transport, as well as for military uses.
Some Zeppelins were seen during a German air raid in 1941. Rose Tyler was hanging onto a small Zeppelin. (DW: The Empty Child)
In Pete's World, zeppelins covered the skies of London and was owned by the richest businessmen. (DW: Rise of the Cybermen)
A Cybus Industries Zeppelin was where Mickey Smith and Jake Simmonds defeated the Cybermen. This Zeppelin was later used as a means of escape from an exploding Cyber-factory. (DW: The Age of Steel)