23 April 1966 – The Vietnam People’s Air Force (VPAF) sent its first MiG-21 to intercept two B-66 Destroyers being escorted to their mission by a flight of F-4 Phantoms. (2) Neither side scored a kill in the engagement. However, also on April 23, 1966, large numbers of MiG encounters in the area had been reported by American pilots. (1)
“The MiG-21 came into use in early 1966. One of the first encounters between a USAF F-105 and a MiG-21 ended as an instructive tale. The USAF pilot locked in combat with the MiG-21 ran out of fuel and had to eject. The F-105 was chalked up as a victory for the North Vietnamese pilot, who was able to return to base. On April 19, 1967, MiG-17s engaged and shot down an F-105. Maj. Leo K. Thorsness pursued another MiG and shot it down with guns. Thorsness intercepted more MiGs lining up for an attack and nearly ran himself out of fuel while acting as a decoy to save other airmen. For his heroic acts, Thorsness was awarded the Medal of Honor.
The North Vietnamese Air Force (VPAF) had between 60 and 75 aircraft in service at most points during the war. Yet the MiG-17s, MiG-19s, and MiG-21s shot down 67 USAF aircraft against a loss of 137 of their own, leaving the US Air Force with barely a two-to-one exchange ratio over the course of the war.” (2)