The first use of air mail in the United States occurred in September, 1911 from Garden City, New York to Mineola, New York. Other experimental airmail flights occurred in that year and successive years. In 1918, Congress appropriated funds to set up an experimental air mail route, which happened on May 15, 1918 with the establishment of a route between New York City and Washington, D.C. with a stopover in Philadelphia. Although initially operated with the cooperation of the War Department, the Post Office Department assumed full control of this service later that year. With the success of this air mail route, plans were made to complete a transcontinental route from New York to San Francisco. By September 8, 1920 the final and most Western leg of this route - Omaha, Nebraska to San Francisco - was put into operation. Congress passed the Kelly Air Mail Act in 1925, which got the government out of the air mail business. It required private carriers to bid on Contract Air Mail (CAM) routes set up by the Post Office.

Some of the planes that were used in air mail service include Curtiss JN 4H, with Wright engine, 150 h.p.; Standard JR-1B, with Wright engine, 150 h.p.; Curtiss R-4-L, with Liberty-12 engine, 400 h.p.; Curtiss HA, with Liberty-12 engine; Twin D.H. with two Liberty-6 (Hall Scott) engines, 400 h.p.; Martin mail planes, with two Liberty-12 engines, 800 h.p.; Junker (JL-6) with B.M.W. engine, 200 h.p., and L.W.F. (type V) with Isotta Fraschini 250 h.p. engines.