Dunlap joined the Royal Canadian Air Force in 1928, earning his pilot's wings at Camp Borden in Ontario.

In his early flying career Dunlap was assigned to aerial photography duties when he mapped out large parts of Canada.

In 1942 he was promoted to group captain and took up command of the air armament school at RCAF Station Mountain View in Ontario.

[2] Dunlap was posted to the United Kingdom in late 1942, becoming Station Commander of RAF Leeming in Yorkshire in January 1943.

[1] In retirement Dunlap worked on a voluntary basis to support the development of the National Aviation Museum in Ottawa.