I have only actively used aircraft in one of the games I have played. The Aztecs came up to my shore with a destroyer and an aircraft carrier in a stack. I didn't have a good port on that side of the map so I built a bunch of jet fighters.

At one point I had over ten jet fighters attacking the stack every turn. They would reduce the destroyer and carrier down to 50% strength and then not be able to attack further.

Is 50% the most damage an air unit can do? You could almost make an argument that an aircraft cannot completely destroy a land unit. However aircraft should be able to sink ships.

With the neutering of artillery and artillery like units, I just went ahead and gave my jets and stealth bombers the ability to do 100% damage.

Its an easy fix with the XML. So far its been pretty decent. IIRC destroyers have a percentage to shoot down aircraft, and jets on carrriers can have a 70% chance of intercept, its been pretty balanced so far.

air units have been able to sink ships since C3C, I don't understand why they changed it this time.