Original: The operator of Heathrow , BAA , claims that Heathrow is the '' world 's busiest international airport '' , but it is only the world 's third-busiest by total passenger traffic , after Atlanta-Hartsfield-Jackson 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 .