Highlight
1938 - Northwest develops the first practical aviation oxygen mask, making possible high-altitude flying over the Rocky Mountains.
1930
July 1: Northwest moves its operations base to St. Paul's Holman Field (today's St. Paul Downtown Airport). First ground radio installation is purchased. Service expands to Rockford and Elgin, Illinois; Janesville, Wisconsin; Sioux City, Iowa, and Omaha, Nebraska.
1931
February 2: Northwest resumes "international" service to Winnipeg. In a compromise to satisfy both U.S. and Canadian governments, Northwest flies to the border town of Pembina, North Dakota, where mail and passengers transfer to Western Canada Airways for the last 67-mile leg to Winnipeg.
June 2: Service expands to Bismarck, Valley City and Jamestown, North Dakota. Duluth, Minnesota, service is added using seaplanes and an amphibian base in Lake Superior.
The fleet expands: two Sikorsky S-38 amphibians are purchased to serve Duluth; the 7-passenger Travel Air 6000 is added.
Arthur R. Rogers of Minneapolis is elected company president.
1933
December 3: Northwest achieves the "northern transcontinental" route to Seattle and Tacoma, Washington. See 80th anniversary blog post.
Service expands to Dickinson, North Dakota; Billings, Glendive, MilesCity, Helena, Butte and Missoula, Montana; and to Spokane, Washington.
The Lockheed Orion, a wooden-frame, six-passenger, retractable-gear monoplane capable of 180 mile-per-hour cruise, joins the fleet.
1934
February 1: President Roosevelt cancels all air mail contracts. In the reshuffle, Northwest loses the Chicago—Fargo route.
April 16: Northwest is reincorporated under Minnesota law as Northwest Airlines, Inc.
Col. Lewis I. Brittin, founder and general manager of Northwest Airways, resigns. Shreve M. Archer is elected president.
December 31: Northwest buys back the Chicago—Fargo mail contract.
Northwest adds the twin engine Lockheed Electra to the fleet.
1935
October 10: Northwest resumes "true" international service to Winnipeg, eliminating transfer at Pembina, ND.
Lewis M. Leffingwell is elected president of Northwest Airlines.
1936
June: Frank Hulse and Ike Jones buy a controlling interest in Southern Airways of Georgia, a fixed-base operator and flight school that becomes the corporate predecessor of Southern Airways, Inc.
1937
July 15: Croil Hunter is named president, the first Northwest Airlines operating officer to hold this title.
The twin-engine Lockheed Zephyr enters service with Northwest.
1938
Northwest assists the Mayo Clinic in developing the first practical aviation oxygen mask, making possible high-altitude flying over the Rocky Mountains.
Service expands to Portland, Oregon, and Yakima, Washington.
1939
Northwest puts its first Douglas DC-3 into service. The twin-engine workhorse carries 21 passengers at 140 mph cruise speed.
Northwest hires its first stewardess to work on the new DC-3.
Frustrated by inconvenient rail service between his home town and Chicago, Walter Olen, president of the Four Wheel Drive Automobile Company of Clintonville, Wisconsin, trades a company truck for a four-seat Waco biplane. FWD's company air shuttle service is the predecessor of North Central Airlines.