Dive-bomber/ground attack fighter were a key factor during World War 2, for they are small enough to bomb a key area without harming the area around it (like a enemy HQ within a town), but, they are big...
Helicopters comes into mass production for military use when World War 2 have ended. As the 2 world superpowers, namely USA and USSR, were at a rush of improving and upgrading their armed forces in case...