Northwest Airlines, Inc., American airline founded in 1926 as Northwest Airways, Inc., and incorporated on April 16, 1934, as Northwest Airlines, Inc. Originally flying a mail route between Chicago and Minneapolis–St. Paul, Minn., the company expanded in subsequent decades to eventually include a domestic and international system radiating from Chicago, Minneapolis–St. Paul, and Seattle, Wash., to other points in the United States, Canada, the Far East, and Europe. Northwest’s parent holding company, NWA Incorporated, was created in a corporate reorganization in 1984. Headquarters are at Minneapolis–St. Paul International Airport.
From 1928 to 1933 Northwest expanded westward, city by city, through the Dakotas, Montana, and Washington state. In 1945, after serving the U.S. government in various northern and Pacific theatres of war, the airline secured an extension of its routes eastward from Minneapolis–St. Paul to New York City, via Milwaukee and Detroit, and thereby became the nation’s fourth transcontinental airline—although, unlike TWA, United, and American, it did not initially serve the California market. The following year Northwest was certified to fly to the Far East and began service in 1947; for a time the airline used the trade name Northwest Orient. In 1958 it secured the lucrative Florida route from the Midwest. Northwest started service to the Benelux countries and London in 1979 and 1980, respectively. In 1982 it established routes to South America and China; the latter had not been linked directly to the United States by air in more than 30 years. In 1986 Northwest purchased Republic Airlines, Inc., thereby acquiring routes to Mexico and the Caribbean.
In the early 1990s Northwest formed a cooperation agreement with the Dutch carrier KLM, and in 1993 the two airlines began a joint operation of U.S.–Europe flights. Northwest subsequently formed other agreements with Delta Air Lines and Continental Airlines. In the early 21st century Northwest faced increasing competition from low-fare carriers, and in 2005 it filed for bankruptcy protection. Three years later, amid rising fuel prices and a slowing economy, Northwest Airlines announced that it was merging with Delta. The new airline would be the largest carrier in the world. In September 2008 Northwest and Delta shareholders approved a deal. The following month, after the U.S. Department of Justice declared that it did not have any antitrust objections, Delta completed its $2.8 billion acquisition of Northwest.