Earlier today, I mentioned the hazards of flying in combat. I’ve come across a good database on the actual numbers. Helicopter Losses During the Vietnam War

6994 UH-1 Hueys served in Vietnam, of which about 3400, nearly half, were lost. A total of about 20,000 pilots flew Hueys, roughly half the chopper pilots who served in Vietnam. 1,151 UH-1 pilots and 1,231 non-pilot crew members were killed, about 5.5% of the total, and about 4% of all US war fatalities.

Army UH-1’s totaled 10,693,902 flight hours in the Vietnam War between October 1966 and the end of 1975. This is by far the highest combat flight time of any aircraft in history.