Pentland served in the fledgling Royal Australian Air Force (RAAF), and later the Royal Air Force, before going into business in 1927. His ventures included commercial flying around the goldfields of New Guinea, aircraft design and manufacture, flight instruction, and charter work. In the early 1930s, he was employed as a pilot with Australian National Airways, and also spent time as a dairy farmer.
Pentland served in both the Royal Australian Air Force (RAAF) and the Royal Air Force before starting his own business in 1927. His ventures included flying for commercial purposes around New Guinea's goldfields, designing and building aircraft, teaching others to fly, and providing charter services. In the early 1930s, he worked as a pilot for Australian National Airways and also had a dairy farm.