The trade group attributes Atlanta's success to its strategic location, where it is within a two-hour flight of 80% of the US population. In addition, the ACI credits the growth of ATL's largest tenant - Delta Air Lines - for the airport's continued expansion in the traffic. Globally, the number of people traveling by air grew, in spite of weakening economic growth, at a rate of 6.4% in 2015 - the highest percentage growth since 2010.
According to the ACI, the number of airports around the world with more than 40 million annual passengers has more than doubled from 16 in 2005 to 37 in 2015. Much of this can be attributed to airlines shifting its capacity away from smaller airports in favor of bolstering its major hubs. The ACI cautions that such behavior could hinder the economic development of the communities in and around smaller airports.
As for this year, the organization believes overall global passenger traffic will continue to increase, but cautions that geopolitical unrest and protectionist economic policies could hinder that growth.
The trade group compiled its report using passenger traffic data from 2,300 airports from 160 countries around the world. Here are the 10 busiest airports in the world based on total passenger traffic: