World War II was an era of rapid innovation and terrible destruction from above. From the invention of radar to the birth of the fighter ace, and from Hitler's blitzkriegs to the bombing of Hiroshima and Nagasaki, this was the period where national air forces came of age, where individual planes coalesced into unstoppable squadrons, and where wartime tactics were dictated from the sky down. Evolving from their roles as spotters, reconnaissance planes transformed into bombers. Germany rained shells down on London, the Allies executed precision bombing raids by day and frightful carpet bombing missions by night. Pathfinders led bomber squadrons to their targets, and fighters protected other planes as they flew. By the time America dropped the atomic bomb - once and for all illustrating the effectiveness of destruction from above - each airplane had its own role, and together, they had made the world a much smaller place to wage war.

Source: Military Channel