Tang Jiyao set up an opium trafficking scheme in Yunnan, with monopolies, taxes and licenses, and succeeded in producing large amounts of opium from poppy plants, which were suited to Yunnan's climate. He transported opium via Indochina to Haiphong, which was a port, from where it was sent to China via the coast. Along with the prospects of exporting homegrown Yunnanese opium and morphia to other provinces, Tang Jiyao maintained his fleet of dozens of combat and transport aircraft based at Kunming Wujiaba airbase which he and Cai E established in 1911, and officially opening Yunnan Aviation School in 1922.