Secondary theaters could remain economically important even when planners expected the main fleet battle elsewhere. Diverting Mediterranean trade around Africa would lengthen the routes needing protection, and a raider there could force the Navy to detach major combat assets. The early use of Courageous and Ark Royal for submarine hunting illustrates the cost of having no suitable smaller aviation ships available. Buying tenders as insurance was difficult to justify when Japan appeared containable at Singapore and Italy at the Mediterranean exits. The same reasoning later relied on blockading Germany in the North Sea, with Norway and France expected to remain outside German control. Those assumptions encouraged concentration of resources but left little reserve capacity if the geography changed.
Notable Point · 39:30-44:43
Why secondary theaters needed their own aviation support
Without cheaper aviation support for distant trade routes, a secondary threat could draw fleet carriers away from the main war.