After leaving Seaboard, Bill continued his career in aviation. His last job was to fly a Stemme ST10 motor glider in connection with the filming of the nature documentary The Leopard Son in Serengeti National Park, Tanzania. The film was directed and photographed by the nature photographer Hugo van Lawick and narrated by Sir John Gielgud. Bill flew the motor glider more than 5,000 miles from the factory in Germany to Tanzania. He died in a crash during the last test flight before the filming was to begin. The film was "Dedicated to the Memory of William Stedman." A companion video, The Making of Leopard Son, features interviews with Bill and shows footage of him flying the motor glider.
Bill is survived by his wife, Jill; and their daughter, Sabrina; and by daughters, Tracy Stedman and Lisa Stedman; son, Jesse; and two grandchildren, Romeo Mouras and Sunny Quailer. He is seen here on a sunny beach in 1968.