1927
July 5: Northwest begins passenger service. St. Paul businessman Byron Webster is Northwest's first ticketed passenger, paying $40 for a 12 1/2-hour, one-way flight from the Twin Cities to Chicago via La Crosse, Madison, and Milwaukee, Wisconsin. Charlie "Speed" Holman, Northwest's first pilot, is at the controls.
Northwest adds the Laird biplane to its fleet for mail service.
In 1927, Northwest carries a total of 106 passengers.
1928
February 1: Northwest becomes an international airline with weekly Twin Cities—Winnipeg flights via Fargo, N.D. After only three month, Fargo—Winnipeg service is suspended due to opposition from the Canadian government.
April 2: The first scheduled air express is carried into the Twin Cities.
September 1: The first coordinated air-rail mail service begins from the Twin Cities to Chicago. Service expands to Green Bay, Fond du Lac, Oshkosh, Neenah-Menasha and Appleton, Wisconsin. Northwest expands its fleet with Waco biplanes, mostly for airmail service; 6-passenger, single-engine Hamilton Metalplanes; and 14-passenger Ford Tri-Motors.
1929
August 1: Twin Cities businessmen led by Richard C. Lilly of St. Paul purchase Northwest Airways from the original Michigan investor group. Lilly is named president.
First night air mail flight between the Twin Cities—Chicago.
U.S. government adopts Northwest's "U.S. Air Mail" pilot insignia for all air mail carriers.
Service expands to Rochester, Minnesota.