Heathrow is also Europe 's busiest airport for passenger traffic , and handles more international passenger traffic than any other airport in the world . It is the fourth busiest airport in the world ( as of 2010 ) in terms of total passenger traffic and it handles more international passengers than any other airport in the world . It is also the busiest airport in the European Union in terms of passenger traffic and the second busiest in Europe in terms of traffic movements , second to Paris-Charles de Gaulle Airport near Paris , France .