The real question is why do I even need an aircraift carrier? It is only a floating airbase after all.
When we talk about carriers, we generally are referring to planes that are on them. Since the planes fighting have been decoupled from the aircraft carrier, and the air craft carrier has horrible combat stats, with the airplanes doing most of the actual fighting.
So Why air we building aircraft carriers?
a) To project airpower at range, because we have no nearby airbases to fight from.
b) Dynamically move the areas we project air power, without having to build new bases.
This make sense in the pacific, that is huge and has few stable airbases. Meanwhile in the European theater since things are closer together, and in range of your airbases you don't need a floating one.