In 1938, only one year before Canada entered World War II,[6] Hartman joined the Royal Canadian Air Force as an aero-engine mechanic.
Without a university degree, his desire to fly Spitfires could not be realized until two years later when Canada lifted education restrictions for pilots, to help with the war effort.
Hartman scored so highly on his flight tests that he was made an instructor for the RCAF for the war's duration in Saskatoon, Saskatchewan.
Hartman stayed in the RCAF until mandatory retirement 25 years later, flying Search and Rescue flights out of Goose Bay, Labrador.
[15][16][17] Hartman was named captain of the all-American National Skeet Shooting Association (NSSA) ten times in the sixteen years that he was a member.