Republic Airlines (IATA: RC, ICAO: REP, Call sign: REPUBLIC) was a domestic airline in the United States, formed by the merger of North Central Airlines and Southern Airways on July 1, 1979. Its headquarters were at Minneapolis-St. Paul International Airport, in what is now Fort Snelling in unincorporated Hennepin County, Minnesota. The former headquarters is now called Delta Air Lines Building C.

History   Republic Airlines began in 1979 with the merger of North Central Airlines and Southern Airways, the first under airline deregulation. The new airline's headquarters was at Minneapolis-Saint Paul International Airport, though its largest hub was at Detroit Metropolitan Wayne County Airport. Republic was then the sixth largest airline in the United States. Following its buyout of Hughes Airwest in 1980, Republic became the largest airline in the U.S. by destinations served. The route network was served with the world's largest DC-9 fleet which included DC-9-10, DC-9-30 and DC-9-50 aircraft and also with Boeing 727-200, Boeing 757-200 and McDonnell Douglas MD-80 jetliners. After the merger, losses mounted and service reductions followed. Saddled with debt from two acquisitions and new aircraft, the airline struggled in the early 1980s, and even introduced a human mascot version of Herman the Duck. It de-emphasized service to Phoenix, a former hub of Airwest, citing its inability to compete with non-union airlines there.    Northwest Airlines   In 1986, Northwest Orient Airlines announced on January 23 that it would purchase Republic for $884 million in response to United Airlines' purchase of the Pacific routes of Pan American World Airways and to provide domestic feed. Opposed by the Justice Department, the Northwest-Republic merger was approved by the Transportation Department on July  and was completed on October 1, with Northwest dropping the word Orient from its name after the merger. Republic's hubs at Minneapolis, Memphis, and Detroit became the backbone of Northwest's domestic route network.   Despite Northwest's efforts to remove all remaining presence of any Republic-branded imagery, it is still possible to find a few old Republic logos around Minneapolis-Saint Paul International Airport and Memphis International Airport. The logos can no longer be seen at Detroit Metropolitan Wayne County Airport because Northwest's old terminal has been demolished. Northwest subsequently merged with Delta Air Lines in 2008; the deal was finalized in January 2010, with Delta as the surviving brand.