 Bowman eventually relinquished his Army commission on joining the Royal Air Force on 1 August 1919, with the rank of flight lieutenant.Bowman served in India in 1920, and was promoted to squadron leader on 1 January 1921.He served in the RAF Coastal Area, and as a supernumerary at the RAF Depot (Inland Area), before attending the Central Flying School for a flying refresher course before embarking for overseas service on 16 January 1922.