Airlink (helicopter shuttle service)
Airlink was the brand name of a helicopter shuttle service which ran between London's two main airports, Gatwick and Heathrow, between 1978 and 1986. Operated jointly by British Caledonian Airways and British Airways Helicopters using a Sikorsky S-61 owned by the British Airports Authority, the "curious and unique operation" connected the rapidly growing airports in the years before the M25 motorway existed.
Source: Wikipedia — Airlink (helicopter shuttle service) (CC BY-SA 4.0)