Delta Airlines is the most popular airline and legacy carrier in the United States. oldest airline in the world . Delta head office Atlanta, Georgia. Delta Airlines Founded, March 2, 1925 , 5400 Delta Flights Daily visits in 52 countries and 325 destinations, Delta airline currently 9 hubs. Atlanta, Boston, Los Angeles ,Minneapolis/St. Paul, New York-JFK , New York–LaGuardia , Salt Lake City , Detroit, Seattle.