In WarBirds, before the CV could be sunk, all escort ships had to first be sunk. This leaves the CV fully vulnerable after escorts are gone. I don't know if this is possible, but here are some thoughts along those lines:
CV currently takes 8K ords to sink and I think it takes 2K ords to sink an escort, or a Cruiser.
So, if we had 8 escorts, including Crusiers, and we sunk 1 escort, or Cruiser in the CV Fleet, then we could reduce the CV's ability to repair itself by 1K. The CV hardness would still be 8K when all escorts and Cruisers are sunk, but, it can no longer repair itself after all of the escorts and Cruisers are sunk. This makes the CV impervious to any attack by Bombers, or Dive bombers, until the escorts and Cruisers are sunk.
The one exception to this would be by Torpedo attack. If Torpedo carrying Aircraft, or PT Boats, can get inside of the escort/Cruiser defensive ring, then two torpedos could sink the CV even if all of the escorts/Cruisers are still up and the only defensive Ack firing would be from the CV.
Just some thoughts...
<S> Semper Fidelis