 In 1927, Pentland formed Mandated Territory Airways with entrepreneur Albert Royal to fly freight to and from the goldfields of New Guinea. The pair bought a DH.60 Moth biplane, which Pentland ferried to the firm's base at Lae in February 1928. The business prospered in the short term, to the extent that the partners took on another Moth and more pilots. By the end of the year, however, Pentland was suffering from malaria and had to abandon the venture, selling one of the planes to Guinea Airways and returning to Australia with the other. After recovering in the new year, he embarked on a series of new enterprises, including aircraft manufacture, a flying school, and charter work. In February 1929, he formed the General Aircraft Company with Royal and another partner to produce an Australian-designed aeroplane, the Genairco, of which eight were eventually sold. With the Moth from Mandated Territory Airways, he established Pentland's Flying School at Mascot, New South Wales. He also flew charters with a Moth owned by The Sun newspaper, using the same aircraft that September to compete in the East-West Air Race from Sydney to Perth, as part of the celebrations for the Western Australia Centenary. The event attracted several veteran aviators of World War I, including Horrie Miller — the eventual winner on handicap — and Charles "Moth" Eaton, whom Pentland beat into fifth place across the line.
