The DC-9 brought modern jet service to many smaller and intermediate sized cities on Delta's routes. Prior to 1965, Delta acquired two jets, the Douglas DC-8 and the Convair 880, for long distance flights between larger cities. The DC-9 filled a different and very important niche at a time when 60% of all U.S. passenger traffic was on routes of 500 miles or less—distances usually served by propeller aircraft such as the Douglas DC-6, DC-7 and Convair 440. The DC-9 was designed to operate from 98% of the nation's airports in 1965. It was the first American-built jet to meet the requirements of smaller and intermediate sized cities. 

Delta leased one DC-9-15 from Jet International and flew 16 of the DC-9-14 type: 14 were purchased from Douglas Aircraft and two were leased from Eastern Airlines. Aircraft N3305L crashed during a training flight at Fort Worth, Texas on May 30, 1972.  

Delta sold its remaining DC-9-14s to Southern Airways in 1972-1973, but the planes became part of Delta's history again when Northwest Airlines merged with Delta in 2008:

• Northwest acquired seven of Delta's original DC-9-14s from a merger with Republic Airlines in 1986: N3306L, N3308L, N3309L, N3310L, N3312L, N3313L and N3314L.
• These former Delta DC-9s became Republic DC-9s when Southern and North Central Airlines merged to form Republic Airlines in 1979.

Other descendants of the original DC-9 joined the Delta fleet in the late 1980s/early 1990s: the McDonnell Douglas MD-82 and MD-88 (originally known as the DC-9-80) in 1987, and the MD-90 in 1995.

After almost a 16-year absence, the DC-9-30 returned to the Delta fleet, and for the first time, Delta flew the DC-9-40 and -50. These aircraft came from Northwest Airlines, which merged with Delta on October 29, 2008; the merged airline began single operations in 2010.

Former Northwest DC-9s added to Delta fleet: 

• 97 aircraft total: 51 DC-9-31/32s, 12 Model 41s and 34 Model 51s. 
• 2 of the Model -32s were former Delta planes: N3324L and N3322L.
• The Model -30s and -41s remained in Northwest colors until they left the Delta fleet in 2010-2011.
• All the former Northwest DC-9-51s were repainted in Delta livery by mid-November 2009. Ship 9863 was last one repainted. 

In 2013, Delta acquired another evolution of the enduring DC-9 design: ex-AirTran Boeing 717-200 jets with delivery through 2015. Learn more. 

DC-9-51 Retires
Delta was the first and the last U.S. airline to fly scheduled DC-9 commercial flights. The official Delta DC-9 farewell took place on January 6, 2014. To acknowledge the DC-9's retirement, the last flight (Minneapolis/St. Paul to Atlanta) was numbered DL2014 noting the final year of service, while the preceding flight (Detroit to Minneapolis/St. Paul) was flight DL1965, the aircraft's initial year of service.

Two DC-9's remained with Delta for several weeks to fill in for delayed Boeing 717 deliveries. On January 22, 2014, Delta operated the final DC-9 flight (DL310) with DC-9, N779NC, flying from Eglin Air Force Base in Valparaiso, Florida, to Atlanta.