|Clifford Makins (Editor). The Eleventh Eagle Annual. London: Longacre Press Ltd., 1962.|
Silver City Airways started as a stunt in 1948, carrying an Armstrong Siddeley car from England to France inside a Bristol Freighter aircraft. When it landed and was unloading, the crew was approached by an observer who needed a way to get his Bentley back to England. This is how the air ferry started. In 1949 the company hired three Freighters, and in spite of the high costs, carried 2,600 cars, 100 motorcycles and 7,900 passengers in that year alone. In 1951, the company expanded to 8 aircraft, and attracted 7,529 cars, 3,240 motorcycles and 30,137 passengers. To get around a law that prohibited passengers from traveling without a vehicle (in order to protect airlines like B.E.A.), Silver City encouraged people to travel with a bicycle, even a borrowed one! Eventually, cows, racehorses, produce and general cargo also joined the manifest.
For the full article, read the High Road to France.
In 1962, economic pressures (including problems associated with its aging aircraft) led to a takeover by a holding company of British United Airways, and in the following year to an amalgamation with Channel Air Bridge, forming British Air Ferries. That entity soldiered on until 1971.
There's much more information at the Silver City Airway's tribute website.