He fought with conspicuous gallantry and intrepidity over Luzon, Philippine Islands. Voluntarily, he led a squadron of 15 P-38's as top cover for heavy bombers striking Mabalacat Airdrome, where his formation was attacked by 20 aggressive Japanese fighters. In the ensuing action he repeatedly flew to the aid of embattled comrades, driving off enemy assaults while himself under attack and at times outnumbered 3 to 1, and even after his guns jammed, continuing the fight by forcing a hostile plane into his wingman's line of fire. Before he started back to his base he had shot down 3 Zeros. The next day he again volunteered to lead escort fighters on a mission to strongly defended Clark Field. During the resultant engagement he again exposed himself to attacks so that he might rescue a crippled bomber. In rapid succession he shot down 1 aircraft, parried the attack of 4 enemy fighters, 1 of which he shot down, single-handedly engaged 3 more Japanese, destroying 1, and then shot down still another, his 38th victory in aerial combat. On 7 January 1945, while leading a voluntary fighter sweep over Los Negros Island, he risked an extremely hazardous maneuver at low altitude in an attempt to save a fellow flyer from attack, crashed, and was reported missing in action. With gallant initiative, deep and unselfish concern for the safety of others, and heroic determination to destroy the enemy at all costs, Maj. McGuire set an inspiring example in keeping with the highest traditions of the military service.