Battle of Britain
At the end of World War I, Orville Wright confided to a friend: "The aeroplane has made war so terrible that I do not believe any country will again care to start a war."
But just over 20 years later, Britain and Germany were engaged in a battle that proved a turning point not only in World War II but also in the use of planes as a killing machine.
Led by the fast and graceful Spitfire and the sturdy, but agile, Hurricane (left), the RAF successfully thwarted German attempts to invade Britain. More than 2,000 aircraft were lost over the summer and autumn of 1940.