Northwest Airlines Corp. (NWA) was a major American airline founded in 1926 and absorbed into Delta Air Lines by a merger that was approved in 2008. Northwest continued to operate under its own name and brand until the integration of the carriers was completed in 2010. The merger made Delta the largest airline in the world until the American Airlines–US Airways merger in 2013.
Northwest was headquartered in Eagan, Minnesota, near Minneapolis–Saint Paul International Airport. After World War II it became dominant in the trans-Pacific market with a hub in Tokyo, Japan (initially Haneda Airport, later Narita International Airport). In response to United Airlines' 1985 acquisition of Pan Am's Pacific routes, Northwest paid $884 million to purchase Republic Airlines and then established fortress hubs at Detroit Metropolitan Wayne County Airport and Memphis International Airport. With this merger, NWA established the domestic network necessary to feed its well established Pacific routes. Lacking a significant presence in Europe, in 1993 it began a strategic alliance with KLM and a jointly coordinated European hub at Amsterdam Airport Schiphol.
Prior to its merger with Delta, Northwest was the world's sixth largest airline in terms of domestic and international scheduled passenger miles flown and the US's sixth largest airline in terms of domestic passenger miles flown. In addition to operating one of the largest domestic route networks in the U.S., Northwest carried more passengers across the Pacific Ocean (5.1 million in 2004) than any other U.S. carrier, and carried more domestic air cargo than any other American passenger airline.
Regional and commuter airline flights for Northwest were operated under the name Northwest Airlink by Big Sky Airlines, Eugene Aviation Services, Express Airlines I/II, Fischer Brothers Aviation, Mesaba Airlines, Northeast Express Regional Airlines, Pacific Island Aviation, Pinnacle Airlines, Precision Airlines, Simmons Airlines and Compass Airlines via respective code sharing agreements.