Sylvio L. Dery entered the military service in Massachusetts. He served as a Technical Sergeant and Flight Engineer in the 791st Bomber Squadron, 467th Bomber Group, Heavy on B24 #42-52445 aircraft during World War II. On April 22, 1944 while returning from bombing the railway marshalling yards at Hamm (Germany), the craft was shot at from the rear by ME-410 intruder aircraft of Kampfgeschwader 51, which had entered the landing pattern of returning aircraft. Seven men were killed (including TSGT Dery) and 3 men bailed out safely. TSGT Dery is now buried in the Cambridge American Cemetery, Cambridge, United Kingdom.