Croydon Airport was the first airport in the world to introduce air traffic control, in 1921. For almost twenty years it was London 's proncipal airport before it was replaced by Northolt Aerodrome, London Heathrow Airport and London Gatwick Airport.

Croydon aerodrome originated as two adjacent World War I Royal Flying Corps airfields - Beddington Aerodrome had been created in 1915 for protecting London against Zeppelin raids, while Waddon Aerodrome was established in 1918 for test flying aircraft produced by National Aircraft Factory No 1. The two airfields were combined into London's official airport as the gateway for all international flights to and from the capital, Croydon Aerodrome opening on 29 March 1920.

It stimulated a growth in regular scheduled flights carrying passengers, mail and freight, the first destinations being Paris, Amsterdam and Rotterdam. In 1923 Berlin flights were added. It was the operating base for Imperial Airways.

In the mid 1920s the airfield was extended, some adjacent roads such as Plough Lane being closed to allow heavier airliners to land and depart safely. A new complex of buildings was constructed adjoining Purley Way, including the first purpose-designed air terminal in the world, the Aerodrome Hotel and extensive hangars, at a cost of £267,000, offically opening on 2 May 1928.

The terminal building, the booking hall within it with its gallery balustraded in the geometrical design typical of the period, and the Aerodrome Hotel were built in the Art Deco style of the 1920s and 1930s. A further item that caught the eye of visitor and traveller alike was the time zone tower in the booking hall with its dials depicting the times in different parts of the world.

The major aircraft used by Imperial Airways were the Handley Page HP42/HP45 four-engined bi-planes. The first monoplane airliners used by Imperial Airways were the Armstrong Whitworth Atlantas, intended for use on the African routes. In 1938 larger four-engined monoplanes, the Armstrong Whitworth Ensign series (G-ADSR) came into service.

In November 1938 the Chamberlain government decided that Imperial Airways, which served Empire routes, should be merged with British Airways Ltd, which served European routes. The new company was known as British Overseas Airways Corporation, BOAC. However, British Airways Ltd operated from Croydon only from March 1937 to May 1938, when it moved to Heston Airport.

When war was declared in September 1939, Croydon Airport was closed to civil aviation. It played a vital role as a fighter station during the Battle of Britain and was attacked in the first major raid over the London area. Factories in its immediate vicinity were almost destroyed with the loss of six airmen and over 60 civilians. In 1944 Croydon became the base of RAF Transport Command, and in due course civil aircraft operations began again. In February 1946, the airport returned to civilian control.

Gradually it became clear that with technical advances, post-war airliners were going to be larger and the use of airports serving capital cities would intensify. Croydon had no room for further expansion and would shortly be too small to meet demand. Heathrow was therefore designated as London's airport and a decision to close Croydon was made in 1952. Blackbushe Airport in Hampshire and Northolt Aerodrome in Middlesex also served airlines operating European scheduled flights during the 1950s. Croydon's last scheduled flight departed on 30 September 1959.