Twitchell was a licensed pilot, and after retiring from films he went to work for Douglas Aircraft. On Jan. 31, 1957, he was the co-pilot on a test flight of a Douglas DC-7B when it had a mid-air collision with an Air Force fighter. He was killed in the crash. The debris landed on the Pacoima Junior High, also killing three boys. One of the students at the school when this happened was Richard Valenzuela, aka Ritchie Valens. It was because of this incident he developed an intense fear of flying. Ironically, he died only a few days after the second anniversary of this crash, in another plane crash.
Served in the US Army Air Force during World War II.
Bore a strong resemblance to John Carroll.