Following the end of the First World War, Bishop traveled and gave lectures across the United States before being approached by fellow Canadian ace (and Victoria Cross recipient) William Barker about a joint venture. Together they created Bishop-Barker Aeroplanes Limited of Toronto – a short lived passenger service.
Bishop and his family moved to Britain shortly thereafter, working at selling a new type of pipe. He did well and made a good living for himself, but the stock market crash of 1929 was devastating to his finances. Bishop, wife Margaret and three children (born while in Britain) moved back to Canada, where he was appointed Vice President of the McColl-Frontenac Oil Company.
By 1931 the clouds of war once again loomed over Europe. Bishop was appointed Honorary Group Captain in the Royal Canadian Air Force. By 1939 he was promoted to the rank of Honorary Air Marshall of the RCAF and made the Director of Recruiting. For his tireless efforts in promoting and recruiting for the Allied cause, Bishop was named Commander of the Order of the Bath and received the Canadian Efficiency Decoration for his efforts.
When the Korean War broke out, Bishop offered to return to his recruitment role, but poor health once again plagued this brave flyer and his offer was declined by the RCAF. William Avery Bishop died peacefully in his sleep on 11 September 1956 while wintering in Florida. He is buried in Greenwood Cemetery, Owen Sound, Ontario.