Mind you, there is more to the airport site than the nature reserve, and Diamond Geezer was not impressed when he visited:
Before the First World, the site was known as Beddington Aerodrome and has been described as the "cradle of British civil aviation". The use of a site as an aerodrome generally prohibits any large obstacles and the Mere Bank was flattened as a result.
In 1915 the Royal Flying Corps took over the newly created Waddon Aerodrome and sent off fighter planes to combat the German Zeppelins. The first National Aircraft Factory was built here in 1918. In 1920, what was Waddon Aerodrome become the Customs Airport of London and then became Croydon Aerodrome.
Eight years later, after the closing of Plough Lane in 1926 and the erection of new buildings and even a hotel, the aerodrome changed name again to become "The Airport of London". During the late 1920's and the '30s, the site was the only international airport in London and ran regular routes to the Indian subcontinent and also to South Africa.
Charles Lindbergh arrived here from Brussels in the 'Spirit of St. Louis' to a crowd of 150,000 people after his solo crossing of the Atlantic in 1927 and Amy Johnson (a fisherman's daughter from Hull) left Croydon Airport on her flight to Australia in 1930. Their legends are still very much associated with the Downs, with the local primary school bearing the name of the aviatrix, whilst a local play-centre bears the moniker of 'The Lone Eagle' himself.
Over the next couple of decades, however, as aeroplanes were increasing in size and therefore the space required to accommodate them and the runways required for take-off and landing grew commensurately, the urban build around the aerodrome impinged upon the amount of space that could be utilised for extensions. 1946 saw the opening of Heathrow as London's primary airport and without the room to expand to accept the new jet liners, Croydon airport eventually closed at the end of 1959.
In 1993, the name for the main area of chalk grassland that thrived after the closure and demolition of the former Croydon Airport within the Sutton boundary was formally changed to that of Roundshaw Downs. It was declared a Local Nature Reserve in 1994.
The western part of Croydon Airport was redeveloped in the 1960s as the Roundshaw housing estate. It's a million miles away from international glamour, more a poor collection of concrete blocks and Wimpey Homes gathered round a Co-op supermarket. You wouldn't live here.The Wikipedia entry for Croydon Airport says there were two other international airports in the South East of England that operated in the 1950s and have now been forgotten. They are Northolt (now known solely as an RAF base) and Blackbushe Airport in Hampshire.