Between July and October 1940, the Royal Air Force fought the Luftwaffe over southern England in the first major campaign fought entirely by air forces. The Germans had 2,500 aircraft; the RAF had fewer than 700 fighters. But the British had radar, a unified command-and-control system, and the advantage of fighting over home territory. Pilots who bailed out could be back in a new aircraft the same day. The turning point came on August 15—"The Greatest Day"—when the Germans lost 75 aircraft to the RAF's 34. On September 15, the Luftwaffe launched its largest daylight raid on London. The RAF scrambled every available fighter. The Germans lost 60 aircraft and shifted to night bombing. Winston Churchill's tribute to the pilots—"The Few"—endures. The Battle of Britain proved that air power alone could prevent invasion and that integrated air defense networks were essential to national survival.