Within a few years, he was running his own small fleet of bush aircraft including ski and float planes.
His company delivered mail, freight, and supplies in the remote areas of the provinces of Manitoba, Saskatchewan, Alberta and into the Yukon and Northwest Territories.
In 1947, the board of directors elected him CPA's president and he embarked on an expansion that made the company the second largest carrier in Canada and the dominant airline of the Canadian West.
In 1949, McConachie obtained landing rights at the Tokyo and Hong Kong airports that opened the door to CPA's highly successful transpacific service to Australia, Asia and the South Pacific.
Named in his honour, "Grant McConachie Way" in Richmond, British Columbia, is the access artery into Vancouver International Airport, home base for Canadian Pacific Air Lines.