Heavy trade did not guarantee peace, since states could still fight major commercial partners. Figures cited for 1937 put the American share at 60 percent of Japan's oil, all of its aviation fuel, and 76 percent of its aircraft, although the source could not be recalled during the discussion. Those supplies supported Japan's war effort while leaving it exposed to any interruption. Japan's naval air arm also differed from its later wartime form: the Zero was unavailable, the A5M was not yet dominant, and older biplanes still filled gaps. A war beginning in early 1939 would therefore start with different endurance and air-combat assumptions from the later Pacific War.
Notable Point · 16:49-19:20
Trade interdependence and prewar Japanese airpower
Extensive American trade sustained Japan's war effort even as relations worsened, while its naval air arm had not yet reached the strength associated with the later Pacific War.