My two cents: it doesnt need to be big, it just needs to have a large portion of its volume appear to be devoted to fighters.
Thats the problem with pretty much all carriers ingame currently, bar the aquillion, they dont have an apparent large hanger bay.
Have some sort of LARGE launch tubes. Have them face both fore and aft, so RP wise the ships commander can launch fighters AWAY from incoming fire, so as to not risk fire entering an open hanger airlock door.