With Malta undergoing heavy Axis aerial attacks and in danger of invasion, the Allies sent reinforcements numerous times between 1940 and 1942. On 2 March 1942, McNair piloted one of 17 Spitfires launched from the British aircraft carrier HMS "Eagle" to the beleaguered island. As a member of No. 249 Squadron RAF, he was frequently engaged in combat in the skies above Malta. He shot down a 109 on 19 March, a Junkers Ju 88 on 26 March, a 109 on 20 April and a Ju 88 on 22 April, making him an ace. He increased his tally by three 109s, on 22 May, 25 May, and 10 June, before being recalled to England for a leave. He was promoted first to flying officer, then to flight lieutenant sometime during this period.