Delta Air Lines (Atlanta) although not yet officially announced, but published in the schedules, is currently planning to operate the last McDonnell Douglas DC-9-51 on January 6, 2014. An appropriately named flight DL 1965 will operate from Detroit to Minneapolis/St. Paul departing DTW at 3:39 pm (1539) and arriving at MSP at 4:43 (1643) followed by flight DL 2014 which will operate from Minneapolis/St. Paul to Atlanta as the last scheduled flight, departing MSP at 7:20 pm (1920) and arriving at ATL at 8:47 pm (2047) local time. An unspecified DC-9-51 will operate the last flights. Photos of the last flights are welcome.
Delta has been gradually dwindling down the former Northwest Airlines (and North Central Airlines) DC-9-51 fleet with 10 retirements in 2011, six in 2012 and four so far in 2013. According to Airliners.net, 14 were still in service as of November 19, 2013. One of these 14 aircraft will operate the last revenue flight on January 6, 2014. The aircraft will be ferried to the desert and eventually broken up for scrap metal.
This is actually the second Delta retirement of the DC-9. Delta previously retired its last original DC-9-32 on January 1, 1993. With the merger of Northwest Airlines on October 29, 2008, the DC-9 type was re-introduced back in the Delta fleet under the Delta name.
Delta Air Lines took delivery of its first 65-seat Douglas DC-9-14 (N3304L) (see N3314L below) on September 18, 1965. The new type entered revenue service on November 29, 1965 as flight DL 791 on the Atlanta-Memphis-Kansas City route.
177 total DC-9s were operated. Delta in its history operated the following DC-9 types:
16 DC-9-14s
1 DC-9-15 (leased from Jet International)
114 DC-9-31/32s
12 DC-9-41s
34 DC-9-51s
Information from the Delta Museum:
Top Copyright Photo: Bruce Drum/AirlinersGallery.com. McDonnell Douglas DC-9-51 N773NC (msn 47775) completes its final approach into Minneapolis-St. Paul International Airport.
Delta Air Lines: 
Bottom Copyright Photo: Bruce Drum/AirlinersGallery.com. Douglas DC-9-14 N3314L sits at the old Atlanta maintenance base on January 27, 1970. The original delivery color scheme of the DC-9-14s included this forward-pointing widget which was later changed to the standard upright widget.
Filed under: Delta Air Lines Tagged: 45709, 47775, ATL, Atlanta, DC9, DC914, DC951, Delta Air Lines, Douglas, Douglas DC9, Douglas DC914, McDonnell Douglas, McDonnell Douglas DC9, McDonnell Douglas DC914, McDonnell Douglas DC951, Minneapolis/St. Paul, MSP, N3314L, N773NC, Northwest Airlines
