Top ten world's busiest airports by passenger traffic are measured by number of total passengers (data provided by Airports Council International and BAA). One passenger is described as someone who arrives in, departs from, or transfers through the airport on a given day. Hartsfield-Jackson International Airport in Atlanta has been the world's busiest airport every year since 2000 whilst London has the world's busiest city airspace with 2 of its airports regularly found in the top ten.
Hong Kong International Airport - Chek Lap Kok, Hong Kong
Total Passenger: 11,098,500Denver International Airport - Colorado, United States
Total Passenger: 11,495,033Paris-Charles de Gaulle Airport - France
Total Passenger: 12,447,664Los Angeles International Airport - California, United States
Total Passenger: 12,630,858Dallas-Fort Worth International Airport - Texas, United States
Total Passenger: 12,833,031Beijing Capital International Airport - China

Total Passenger: 15,153,600
Tokyo International Airport - Japan
Total Passenger: 15,180,894London Heathrow Airport - United Kingdom
Total Passenger: 15,268,609O'Hare International Airport - Chicago, Illinois, United States
Total Passenger: 15,346,475Hartsfield-Jackson Atlanta International Airport - Georgia, United States

Total Passenger: 20,181,931