During World War II, combat aircraft flew close-air-support to protect soldiers on the ground, but at the time, the air forces were part of the Army. The Air Force didn't become an independent service until after WWII, at which time its generals—fresh from the strategic bombing campaigns over Germany and Japan, and eager to devise new aircraft and war plans based on the A-bomb—scrapped the close-air-support mission. This is why the Army started making combat helicopters. A postwar interservice accord gave the Air Force exclusive right to deploy fixed-wing aircraft, and the Army needed something to cover its ground troops.