Rayner relinquished his acting rank of captain in the Fusiliers on 16 January 1917,[REF] and on 22 February was appointed a flying officer (observer) in the Royal Flying Corps with the rank of lieutenant, with seniority from 18 January 1917 [REF].
He gained his first aerial victories on the evening on 5 September when he set one German Fokker D.VII aflame and drove another down out of control over Avesnes-le-Sec.