London has five airports : Heathrow, Gatwick, Stanstead, London City and Luton. The first three have underground connections to the centre of London and are the main London airports.
Heathrow and Gatwick Airports are the two main centres for overseas flights. London (Heathrow) Airport is one of the largest airports in the world and has two tube stations.
The number of passengers arriving and departing to or from London's airports equalled over 120 million in 2004. Heathrow handled 67m passengers, making the airport the busiest and best connected in the world. Source; CAA, BAA