During the war years, he financed the "Flying Tigers"—the American mercenary group that was later incorporated into the United States Air Force. Gen. Claire Chennault was listed as an employee of the Bank of China. On this project Soong worked very closely with his sister, Madame Chiang Kai-shek (May-ling Soong). He once remarked to John Paton Davies, Jr., one of the China Hands, that there were no U.S. State Department memos sent from China that he did not have access to within a few days.