McKennon entered the
U.S. Army Air Corps in early 1941 hoping to become a pilot but was refused because of insufficient aptitude. He then enrolled in the
Royal Canadian Air Force where he successfully underwent pilot training and became a sergeant pilot by the end of 1941. He was sent to England and became a member of the famous
Eagle Squadron, training with the
Royal Air Force throughout 1942. In November 1942, he was transferred back to the United States Army Air Force with the rank of second lieutenant. He was assigned to the
335th Fighter Squadron of the
4th Fighter Group based at
Debden near
London. McKennon quickly proved his worth as a fighter pilot, shooting down four enemy aircraft while flying the
P-47 Thunderbolt. His group then transitioned to the
P-51 Mustang, in which on March 6, 1944, he downed a fifth enemy plane and earned his designation as an ace. McKennon subsequently served as flight commander and destroyed several other enemy aircraft. After a promotion to
captain, McKennon took command of the 335th Fighter Squadron. He was shot down by flak on August 28, 1944, near
Niederbronn, France, and bailed out safely. With the help of the
French resistance, he evaded capture and safely returned to London on September 24, 1944. This time a
major, he was shot down again while attacking ground targets near Berlin on March 18, 1945. His wingman, Lt. George Green, landed in a nearby field to pick him up. The two pilots disposed of their parachutes to make room, and McKennon flew back to Debden sitting on Green's lap. During the strafing/escort mission on April 16, 1945, his aircraft was once again hit by enemy AA fire and wounded. When the war ended, McKennon was credited with 12 aerial victories and 9.83 ground victories. This odd fraction is explained by the fact that McKennon shared one victory with another pilot (1/2 victory = .50) and another one with two other pilots (1/3 = .33). ==Post war==