High Quality Content by WIKIPEDIA articles! The world`s busiest airports by passenger traffic are measured by number of total passengers (data provided by Airports Council International). 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, although with all airports combined London has the world`s busiest city airport system.