were produced. War surplus aircraft gave way to types specifically designed for civilian service. By the 1930s enclosed cabins greatly improved pilot and passenger comfort. Although mail had been carried by air in various demonstrations throughout the early 1920s, it was not until 1927 that the Post Office started regular use of air mail. Aviation regulation and a new air force The Canadian Air Board was founded 1919 and had regulatory control over all civil and military aviation, merging into the Department of National Defence (DND) in 1923. The Aeronautics Act of 1919 established federal control over aviation and gave the legislative authority for air regulations. With the merging of the Air Board with the DND in 1923, the Canadian Air Force, which had been formed in 1920 as a training establishment, took over from the Air Board and became responsible for all civil and military aviation. The CAF became "Royal" in 1924 and continued with civil flying operations and control until 1926. In that year, the Directorate of Civil Government Air Operations (CGAO) took over responsibility for all non-military aviation regulations. In 1936, the Canadian Privy Council decided that aviation was subject to Federal regulation. This later allowed the Department of Transport, as CGAO was renamed, to become the civil authority over aviation in 1936, taking over from the Department of National Defence. In the late 1930s, the priorities of the Royal Canadian Air Force became focussed on increasing its strength as a military organization. Building the airway system By 1927, a system of airways crossing the country had been proposed. The plan was to provide a major airport every 100 miles, with emergency landing strips every thirty miles, across the country. Airfields were equipped with navigational and runway lighting. Navigation beacons were provided. During the Great Depression starting in 1932, many unemployed men were put to work clearing air strips with hand tools and horse-drawn machinery, as a method of providing some employment. By 1937, the airway system stretched from Vancouver to Sydney, a distance of 3108 miles. In 1928, the Dominion Meteorological Service began providing aviation weather forecasts, but this was suspended in 1932 due to government austerity during the Depression. On initiation of Trans-Canada Air Lines, in 1936 aviation weather forecasts were once again provided, with forecasting stations at Moncton, Toronto, Kapuskasing, Winnipeg, Lethbridge and Vancouver, and intermediate weather stations. Later in the 1930s, surveying and