C-130 Hercules
From Tardis Wiki, the free Doctor Who reference
The C-130 Hercules was a type of military transport aircraft.
UNIT had a command centre in the cargo hold of a EC-130H Hercules military transport aircraft and could use the plane itself as a mobile base. (TV: The Invasion)
According to The UNIT Dossier written by James Stevens for the Daily Chronicle, which was pulled from publication at the eleventh hour, UNIT had yet to acquire a permanent headquarters at this time. (PROSE: Who Killed Kennedy)