The average infantryman in the South Pacific during World War II saw about 40 days of combat in four years. The average infantryman in Vietnam saw about 240 days of combat in one year thanks to the mobility of the helicopter.
The helicopter ushered in a radically different way of fighting a war: instead of armies engaging each other across vast fronts, advancing slowly, and holding ground, the U.S. Army would quickly carry troops into hostile territory and deploy them, then removing them after the fighting ended. While the overall strategy was questionable—no territory was ever really held—the tactic was often very successful. Helicopters offered high mobility for troops and a tremendous element of surprise. An enemy that had been sitting unchallenged for days or weeks could suddenly, without warning, find itself under assault from troops brought in by helicopter. Large troop transport helicopters like the CH-47 Chinook were developed for this purpose, but the workhorse UH-1 Huey became the most popular helicopter for moving troops into and out of battle.
The Army also used armed helicopters to support ground troops, eventually fielding dedicated helicopter gunships like the AH-1 Cobra. A helicopter could be equipped with guns, grenade launchers, rockets, or even guided missiles, and provide rapid and wide-ranging fire against an adversary on the ground. By the middle of the war, the helicopter had become as important to the Army as the tank, the armored personnel carrier, and the jeep, and the Huey was the most symbolic weapon of the Vietnam War.
“Air mobility” came at a heavy price, however. During the Vietnam War, between 1962 and 1973, the United States lost 4,869 helicopters to all causes (with more than a thousand lost in 1968 and another thousand in 1969). Fifty-three percent of these losses were due to enemy fire (including enemy attacks on airbases). The rest resulted from operational accidents. The high rate of operational accidents occurred largely because helicopters are prone to mechanical breakdown if not regularly maintained, and during a war, maintenance often suffers. Vietnam’s heavy jungle canopy also made helicopter operations difficult, with few places to land a stricken helicopter.
MEDEVAC helicopters flew nearly 500,000 missions. Over 900,000 patients were airlifted (nearly half were American). The average time lapse between wounding to hospitalization was less than one hour. As a result, less than one percent of all Americans wounded who survived the first 24 hours died. [VHPA 1993]
The helicopter provided unprecedented mobility. Without the helicopter it would have taken three times as many troops to secure the 800 mile border with Cambodia and Laos (the politicians thought the Geneva Conventions of 1954 and the Geneva Accords or 1962 would secure the border) [Westmoreland]
Approximately 12,000 helicopters saw action in Vietnam (all services). [VHPA databases]
Army UH-1’s totaled 9,713,762 flight hours in Vietnam between October 1966 and the end of American involvement in early 1973. [VHPA databases]
Army AH-1G’s totaled 1,110,716 flight hours in Vietnam. [VHPA databases]
It is believed that the Huey along with the Huey Cobra had more combat flight time than any other aircraft in the history of warfare assuming you count actual hostile fire exposure versus battle area exposure. As an example, heavy bombers during World War II most often flew missions lasting many hours with only 10 to 20 minutes of that time exposed to hostile fire. Helicopters in Vietnam seldom flew above 1,500 feet which is traffic pattern altitude for bombers and were always exposed to hostile fire even in their base camps.