Original: BAA claims that Heathrow is the "world's busiest international airport", but in 2010 it was only the world's fourth-busiest by total passenger traffic, after Atlanta, Beijing and Chicago O'Hare which are also international airports.
Simplified: Heathrow is also Europe's busiest airport for passenger traffic, and handles more international passenger traffic than any other airport in the world. Heathrow is owned and operated by BAA Limited, which also owns\/operates six other UK airports and is itself owned by an international consortium led by the Spanish Ferrovial Group.