Delta Air Lines, Inc. (NYSE: DAL) is an American airline headquartered in Atlanta and the world's largest airline by fleet size, destination, and passenger revenue. Delta operates an extensive domestic and international network, spanning North America, South America, Europe, Asia, Africa, the Middle East, the Caribbean, and Australia. Delta and the Delta Connection carriers fly to 367 destinations in 65 countries (excluding codeshare), across six continents. Delta operates its largest hubs at Hartsfield-Jackson Atlanta International Airport and Detroit Metropolitan Wayne County Airport. Delta Air Lines is a founder and part of the SkyTeam airline alliance.

On October 29, 2008, Delta completed its merger with Northwest Airlines to form the world's largest commercial carrier.In February 2009, the airline began consolidating gates and ticket counters at airports where both Delta and Northwest operate. The consolidation was completed February 2010.On December 31, 2009, the Federal Aviation Administration granted Delta's request to allow Delta and Northwest to operate under a single operating certificate.

Formed as Huff Daland Dusters, Incorporated, an aerial crop dusting operation, on May 30, 1924, in Macon, Georgia, the company moved to Monroe, Louisiana in Ouachita Parish in northeastern Louisiana, in 1925, and began acting as a passenger airline in late 1929. Collett E. Woolman purchased the company on September 13, 1928, and renamed it Delta Air Service , with headquarters in Monroe.In the ensuing decades, Delta grew through the addition of routes and the acquisition of other airlines. It transitioned from propeller planes to jets in the 1970s, and entered international competition to Europe in the 1970s and across the Pacific in the 1980s.