Northwest Airlines was a major commercial airline in the United States from 1926 to 2010. It was originally founded as Northwest Airways by Minnesota entrepreneur Colonel Lewis Hotchkiss Brittin (1877-1952) in 1926 and was based out of Minneapolis, Minnesota. Its initial operation was flying airmail between the Twin Cities and Chicago. By 1927, it began carrying passengers and in 1933 the airline was selected to fly the Northern Transcontinental Route to Seattle, Washington. Due to the Air Mail Scandal of 1934, the company reincorporated as Northwest Airlines, Inc.

From 1947 until 1986, the airline was known as Northwest Orient Airlines. The word "Orient" was used after the airline expanded its route map to include flights to Asia. It was removed from the airline name after the 1986 merger with Republic Airlines.

During World War II, the company set up and operated a military cargo route to Canada, Alaska, and the Aleutian Islands. Scheduled service to eastern Asia began on July 15, 1947, with stops in Tokyo, Seoul, Shanghai, and Manila. The company reached the U.S. East Coast in the late 1940s and began the first transcontinental air coach service in 1949. Service to Hawaii was inaugurated on December 22, 1948. Northwest participated in the Korean Airlift from 1950 to 1953 during the Korean War.

The Airline Deregulation Act of 1978 ended government control of airlines. Northwest continued to thrive in the more competitive market. In the following year, it added more than twenty domestic markets and began transatlantic service to Sweden and Denmark.

A holding company, NWA Inc., was created in 1984, with Northwest Airlines as its principal operating subsidiary. That same year Northwest entered into a marketing agreement with Mesaba Aviation Inc., a Minnesota-based regional carrier, under which Mesaba operated as Northwest Orient Airlink. NWA Inc. was taken private in 1989 after a leveraged buyout. Struggling with debt from the buyout, Northwest sought financial aid from the Minnesota legislature in 1991. By 1993, even with the help of millions in public funds, the airline was near bankruptcy. Employees agreed to significant wage and benefits concessions resulting in saving the company. The airline’s profits rose dramatically during the mid-1990s.

Northwest experienced the first of several setbacks in 1998. First a pilots’ strike stopped service for nearly three weeks. Then the September 11, 2001, terrorist attacks caused the company to reduce its flight schedule, lay off 10,000 workers, and heighten security. In 2003, the company cut flights again due to unrest in Iraq. In 2005, Hurricane Katrina destroyed oil rigs in the Gulf of Mexico, causing the price of fuel to rise. Northwest responded by cutting wages and selling off aircraft.

These measures failed to save the faltering airline. In 2005, Northwest filed for bankruptcy. It emerged from reorganization in 2007. Executives announced a merger with Delta Air Lines, Inc. the following year. Northwest officially became Delta on January 1, 2010.