Chicago Tribune April 7, 1929
All Airlines Lead to Chicago
This map of the principal air transport lines of the country shows Chicago’s preeminence as the natural aviation center of America.
Main lines operating in and out of Chicago, with their equipment and routine business, are indicated on the map by numbers. as follows:
1-National Air Transport. New York-Chicago-Dallas: 6 tri-motored cabin planes: 30 smgle motors. Passengers and mall.
2-Universa! Air Lines, Chicago to Cleveland. Twin Cities. St. Louis, Kansas City and Omaha; 8 tri-motors; 12 single motored planes. Passengers and mail.
3-Boeing Air Transport, Chicago to San Francisco and the west coast: 4 tri-motored planes: 29 single motored. Passengers and mail.
4-Embry-Riddle Co., Chicago to Cincinnati; 8 single motored planes. Passengers and mail.
5-Northwest Airways. Chicago to Twin Cities and to Green Bay. Wis.; 2 tri-motors; 3 single motors. Passengers and mail.
6-Stout Air Lines. Chicago to Detroit; 3 tri-motored planes. Passengers only.
7-Thompson Aeronautical Corp., Chicago to Bay City and Muskegon; 4 single motored planes. Mail only.
8-Western Air Express. Los Angeles and San Francisco by rail and air to New York wIth air transfer junctions to Chicago at several points. Equipment not completed as this page went to press. Passengera and mail.
9-Interstate Airlines, Inc., Chicago to Atlanta, Ga.; 4 aingle motored planes. Passengers and mail.
Other colored lines indicate commercial and mail airplane routes in other sections.