When North Korea invaded South Korea June 25, 1950, the U.S. Air Force (USAF) was less than three years old. Prior to September 1947, the USAF was the U.S. Army Air Forces. Thus the Korean War was its first conflict—a tough, grueling conflict—as an independent service. On November 8, 1950, 1st Lt. Russell Brown, flying an F-80, shot down a MiG-15 in the first all-jet dogfight in history. It was apparent, however, that the MiG-15 was superior to any aircraft then in FEAF's inventory. For a time the B-29s continued bombing targets in northwest Korea by day, but when MiG-15s shot down five Superfortresses in a week in October 1951, the big bombers began attacking only at night. Day after day, though, the Sabres (joined by F-84 Thunderjets or F-80s) swept into MiG Alley to meet the MiG-15s rising from their fields in Manchuria. The age of straight-winged jets had gone. The Americans had proved the power of the USAF and the Russians had proved the power of the MiG. The jet age had arrived.