During the third doctor's time on Earth he found it necessary to design a vehicle which could provide him with more mobility that any "man-made" machine could offer.
This jet-powered car was unlike anything ever seen on Earth before. It hovered above ground on a cusion of air. Increasing the power and lift gave it the ability to fly. This was of great advantage to the Doctor, as any place on the Earth was easily within his reach within a short space of time.