 Mayer was credited with four victories on 7 January 1944, three B-24s and one B-17 shot down in the vicinity of Orléans.On 4 February 1944 he claimed a P-47 from the US 56th Fighter Group, the only American fighter lost by the 8th Fighter Command on this date.It was 100th victory, and he became the first fighter pilot on the Channel Front to achieve this mark.