After watching a Marine Corps aerial team, led by Capt. Clayton Jerome, perform aerobatics in open-cockpit biplanes, he was determined to become a Marine aviator. Foss worked at a service station to pay for books and college tuition, and to begin flight lessons from Roy Lanning, at the Sioux Skyway Airfield in 1938, scraping up $65 to pay for the instruction. His younger brother took over the management of the farm and allowed Foss to go back to school and graduate from Washington High School in Sioux Falls. He graduated from the University of South Dakota in 1939 with a degree in business administration.