Whomobile

The Whomobile was a futuristic-looking vehicle designed by the Doctor, which was similar to a hovercraft and also capable of flight.

The Doctor first used the vehicle to search for the secret base of Operation Golden Age. (DW: Invasion of the Dinosaurs) It was later used to chase after Lupton when he stole the Doctor's Metebelis Crystal. (DW: Planet of the Spiders)

Behind the scenes
The vehicle, which was also known as Alien, was never given a name on screen. It did not appear at all in the first story's original script or novelisation, both in which the Doctor used a motorbike.