Popular comparisons often say the United States chose air-group size while Britain chose armor, but all three leading carrier navies wanted both. A 27,000-ton design could combine the two, yet cumulative treaty allowances permitted only about five such ships for Britain or the United States and roughly three for Japan. Maintenance and refit would leave only two or three available in the larger fleets and perhaps one in Japan's. Cutting designs back toward 20,000 tons therefore imposed severe tradeoffs among protection, aircraft capacity, and the number of usable hulls.
Notable Point · 4:22-5:55
Treaty tonnage forced armor-versus-air-group choices
British, American, and Japanese carrier designers wanted both protection and large air groups, but cumulative treaty limits made that combination too costly in hull numbers.