For over a year, Shomo was assigned to the 82nd Tactical Reconnaissance Squadron. His unit had moved from airstrip to airstrip along the northern coast of New Guinea and then to Morotai supporting General MacArthur's drive to the Philippines performing dangerous photo recon and ground attack missions. His squadron was equipped with older P-39 Airacobras and Curtiss P-40s, which were adequate for the photo recon/ground attack role, but too short-ranged to reach areas where they might encounter Japanese aircraft.
In December 1944 the squadron was given F-6Ds; Mustangs designed for armed photo reconnaissance. On the 24th of that month Shomo was put in command of the squadron and ordered to move it to Mindoro, an island off the southwest coast of Luzon, to support MacArthur's landing at Lingayen Gulf. During that landing on 9 January, Shomo led his first combat mission in the squadron's new planes. The low-level recce was to gather intelligence on the air strength of Japanese in northern Luzon. They approached the Japanese airfield at Tuguegarao where he scored his first air victory, an Aichi D3A "Val" dive bomber, coming in on its final approach.
Two days later on 11 January 1945 Captain Shomo performed the feat that earned him the Medal of Honor. While he and his wingman, Lt. Paul Lipscomb, were heading north for the Japanese airfields at Tuguegarao, Aparri, and Laoag, they saw several enemy planes flying south at about 2,500 feet. Despite being obviously outnumbered, they immediately pulled Immelman turns and found themselves behind 11 Ki-61 "Tonys" and 1 Ki-44 "Tojo" escorting a G4M "Betty" bomber.
On their first pass through the formation Shomo closed to less than 40 yards before opening fire. He shot down four Tonys, then came up under the bomber, firing into its belly. The bomber caught fire and began to lose altitude as its pilot attempted to crash-land the plane. Two of the Tonys escorting the bomber stayed with it as it went down. Shomo pulled up in a tight vertical spiral to gain altitude while the Tojo turned to engage him. The Japanese fighter fired until it stalled and slipped into the clouds. The Betty exploded as it bellied in, and the two escorting Tonys broke away, staying low. Shomo made a second diving pass at the two Tonys and downed them both. In under six minutes, Bill Shomo had shot down seven enemy planes, becoming an "ace in one day." Only one other American fighter pilot scored more confirmed victories in a single mission - Navy Cmdr David McCampbell, CAG-15 aboard USS Essex (24 Oct.1944 9-confirmed victories + 2 probables). Meanwhile, his wingman shot down three of the remaining six planes. The surviving three Japanese planes fled the encounter.
By 1 April 1945, Shomo had been promoted to major and was awarded the Medal of Honor for leading an attack against heavy odds and destroying seven enemy aircraft.
Though Shomo flew more than 200 combat missions, he saw only a total of 14 enemy aircraft from his cockpit. He destroyed more than half of them. He would stay with the Air Force after the war. He was promoted to lieutenant colonel on Feb. 20, 1951. He then went to Colorado and served in operations and training assignments for a year. In March 1952, he became Executive, Commander and Administrative Officer for the 175th Fighter Interceptor Squadron at Rapid City AFB, S.D. He directed Combat Operations. at HQ. 31st Air Division, St. Paul, Minn., for about a year, then became commander of the 14th Fighter Interceptor Squadron at Sioux City, Iowa He commanded a similar squadron, the 59th, at Goose Bay, Labrador, in January 1955, and that June led the squadron to victory in the Northeast Air Command Rocket Meet. Colonel Shomo next became Commander of Headquarters 473rd Air Defense Group and in July 1957, took over the 54th Fighter Group at Greater Pittsburgh Airport. In Jan. 1958, he became Executive Officer for HQ 79th Fighter Group, Youngstown Municipal Airport, Ohio. His last assignment was Thule, Greenland, with the 4683rd Air Defense Wing.
Shomo had been in the undertaker business before the war. He named all his aircraft "The Flying Undertaker" (plus the appropriate numeral) to note this. The F-6D in which he won his Medal of Honor was number "6".
William Shomo is buried in St. Clair Cemetery in Greensburg, PA.
Maj. Shomo was lead pilot of a flight of 2 fighter planes charged with an armed photographic and strafing mission against the Aparri and Laoag airdromes. While en route to the objective, he observed an enemy twin engine bomber, protected by 12 fighters, flying about 2,500 feet above him and in the opposite direction Although the odds were 13 to 2, Maj. Shomo immediately ordered an attack. Accompanied by his wingman he closed on the enemy formation in a climbing turn and scored hits on the leading plane of the third element, which exploded in midair. Maj. Shomo then attacked the second element from the left side of the formation and shot another fighter down in flames. When the enemy formed for Counterattack, Maj. Shomo moved to the other side of the formation and hit a third fighter which exploded and fell. Diving below the bomber he put a burst into its underside and it crashed and burned. Pulling up from this pass he encountered a fifth plane firing head on and destroyed it. He next dived upon the first element and shot down the lead plane; then diving to 300 feet in pursuit of another fighter he caught it with his initial burst and it crashed in flames. During this action his wingman had shot down 3 planes, while the 3 remaining enemy fighters had fled into a cloudbank and escaped. Maj. Shomo's extraordinary gallantry and intrepidity in attacking such a far superior force and destroying 7 enemy aircraft in one action is unparalleled in the southwest Pacific area.