The point is that from 1940-1942, a bunch of planes wandering around patrolling the seas were not an effective anti submarine force. In order to make the air power effective, they needed a convoy system, radar, radar detection, radio coordination and direction, corvettes, sloops, escort destroyers, escort carriers, armed merchant ships as ersatz carriers, the hedgehog and other forward firing weapons, ASDIC, tactical refinements, breaking the enigma code, tight tactical coordination between escorts, and finally to keep the subs on the defensive by making sure that the coverage was so complete that even if they were not destroyed, the submersibles could only fight underwater, could only recharge at night, and risked being destroyed by DEs, PBYs and leigh light carrying british bombers every time they attempted to attack.
In Axis and Allies, all of these things are simulated by requiring you to have a destroyer unit that costs 8.
There are no granular techs. There are no corvettes, armed cruisers, escort carriers, sea planes, depth charges or any other tactical considerations in a strategic game. This is not that kind of game.