The voice of John Holland, playing British Col. Willoughby, is dubbed by another actor; Holland was American, not British, and apparently his accent wasn't sufficiently British, so his voice was substituted with that of an actual British actor.
The name of Major Bently Royce is derived from the the two most famous British car marques, Bentley Motors and Rolls-Royce Motors.
The character played by Willis Bouchey, "Col. Herman Saunders", is named after one of the show's producers, Herman S. Saunders.