His parents came from Lithuania in 1904, settling in the old "Lithuanian Downtown" in Chicago's Bridgeport neighborhood where Vaitkus was born three years later. He enlisted in the army in 1928, and after graduating from advanced pilot’s training school, was commissioned a second lieutenant in the Air Corps. In 1931, he was placed in the reserves with the rank of first lieutenant and returned to civilian life to work with his father-in-law who operated a flying school in Kohler, Wisconsin.