 Heathrow is the largest airport in the country , handling over 67 million terminal passengers in 2006 , making it the third busiest airport in the world , and the busiest if measured by the number of international passengers . Nearly a third of all overseas residents visiting the UK enter the country via this airport , which also handles more than a fifth of all overseas visits by UK residents . Even though there are no dedicated freight services operating out of Heathrow , the practise of transporting cargo in the holds of passenger aircraft means that this airport still accounts for more than half of all freight handled by UK airports . Gatwick airport , with 34 million terminal passengers , is the second largest in the country , eighth busiest in the world for international passenger traffic , and lays claim to the busiest single runway airport in the world . Between them the five London airports handle nearly 137 million terminal passengers , 59 per cent of the national total . Stansted and East Midlands airports have both experienced large growth in freight handling over the past decade , and these two airports are the major hubs for express freight operations . 
