During the summer of 1917, Trevor S. Tait postponed his studies at Yale University in order to volunteer for service with the new branch of the military, the U.S. Air Service. He received his initial pilot training at the newly opened ground school at Cornell University in November 1917. After graduating in February 1918, he was ordered to Camp Dick at Dallas, Texas, and then Love Field, also near Dallas. In October, 1918, he was commissioned, given pursuit classification, and ordered to Carlstrom Field at Arcadia, Florida. After graduating as a pursuit pilot in November, 1918, he was sent to Dorr Field, near Arcadia, for aerial gunnery training. Upon graduation, World War I having already ended, he was provided with an emergency discharge so that he could begin his freshman year at Yale.