Caspar John's force concept treated carriers and submarines as two sides of the same offensive problem. A powerful carrier air group could drive back maritime-patrol and anti-submarine aircraft, giving friendly submarines more freedom to operate. An opponent trying to strike the carrier would first face the submarine screen, while forces hunting those submarines would encounter carrier aircraft. The arrangement created a catch-22 in which concentrating on either arm exposed the attacker to the other. Carrier aviation thus protected a wider naval system instead of serving merely as an air wing attached to one ship.
Notable Point · 24:30-25:47
How carrier airpower frees submarines for offensive action
Caspar John's force concept paired carrier aircraft with submarines so each arm complicated the enemy's attempt to hunt the other.