sentences:  Smith later worked as a test pilot and instructor after the American entry into World War I; he had originally sought to enroll in the United States Army's Air Service, but was refused.His height (5 feet 3 inches) was mentioned as one possible reason for the refusal; the numerous injuries he had suffered in earlier crashes were another.During the war, he was stationed at Langley Field, Virginia and McCook Field, Ohio; he was one of two men trained to fly the De Bothezat helicopter, an early quadrotor helicopter.