Delta Air Lines may control more than three-quarters of the market at the world's busiest airport, but it isn't the largest airline in the industry.
That title belongs to American Airlines, which acquired US Airways in December 2013 to become the world's largest carrier.
Delta once was the world's largest carrier, after its 2008 acquisition of Northwest Airlines. But it was quickly surpassed by a merged United Continental in 2010, putting Delta in the No. 2 spot followed by American Airlines in the No. 3 spot.
Then the newly merged American-US Airways surpassed United, creating a new lineup with American at the front in 2014.
Delta has been in the No. 2 spot based on the number of passengers carried since 201Numero3!
4 and based on operating revenue since 2013.
And now, based on 2015 passenger traffic figures, Delta also takes the No. 2 spot away from United in revenue passenger miles, an industry measure of passenger traffic.
Southwest is the third-largest based on the number of passengers carried, but United is the third-largest based on revenue passenger miles.