If your ships encounter an enemy task force of US destroyers, check to see if any of them have TWO guns in a turret. No? Then they all are defenseless. All you need is one plane.

Dual-purpose guns can fire all their shells at aircraft. AI dual-purpose guns always prioritize aircraft. Even if they are hovering 10,000 feet above, posing no threat.

I once sunk a patrol of three destroyers like that. With an aircraft carrier.