London Heathrow Airport or Heathrow (IATA: LHR, ICAO: EGLL), located in the London Borough of Hillingdon, is the world's busiest airport in terms of international passenger traffic. It is the world's second busiest airport in total passenger traffic. It is also the largest and busiest airport in the United Kingdom. It is also the busiest in the European Union in terms of passenger traffic and the second busiest in terms of traffic movements.[3] Heathrow is owned and operated by BAA, which also owns and operates six other UK airports.[4] BAA in turn is owned by an international consortium led by Spain's Ferrovial Group.[5] Heathrow is the primary hub of British Airways, BMI and Virgin Atlantic.

Located 12 NM (22 km; 14 mi) west[1] of Central London, Heathrow originally was designed to have six runways in three pairs spaced approximately 120 degrees apart but now has just two parallel main runways running east-west and five terminals. The site covers 12.14 square kilometres (4.69 sq mi). Terminal 5 was officially opened by H.M. Queen Elizabeth II on 14 March 2008 and opened to passengers on 27 March 2008. Construction of Heathrow East, to replace Terminal 2 and The Queen's Building, began in 2009, and is expected to be completed in 2013.[6] Terminals 3 and 4 will also be refurbished during this period.[7] In November 2007 a consultation process began for the building of a new third runway and was controversially[8] approved on 15 January 2009 by UK Government ministers.[9]

Heathrow Airport has a CAA Public Use Aerodrome Licence (Number P527) that allows flights for the public transport of passengers or for flying instruction.[10]