Letson flew 35 combat bombing missions over Europe from July 13 to December 14, 1944 aboard a B-17 named "Boulder Buf." In addition to Letson (navigator), other crew members included Max Miller (pilot), Harry Moulton (co-pilot), Dana Clark (radio operator), Roger Welk (bombardier), Bob Torber (flight engineer), Mike Navarro (tail gunner), Dwight Upton (ball turret gunner), and Paul Miller (waist gunner).