Delta Air Lines is the world’s largest airline by annual revenue and one of the oldest existing airlines. Delta operates a fleet of 987 aircraft to over 300 destinations, making it one of the largest in terms of fleet size and destinations served. Of the 198 Airbus A321 aircraft in Delta’s fleet, 71 are A321neos with an average age of 1.7 years. The airline operates out of nine major hubs in the United States, including Atlanta Hartsfield-Jackson International (ATL), Boston Logan (BOS), Detroit Metropolitan (DTW), John F. Kennedy International (JFK), LaGuardia (LGA), Los Angeles International (LAX), Minneapolis International (MSP), Salt Lake City (SLC), and Seattle Tacoma International (SEA).