I never use carriers because their slow, expensive, and only carry a small amount of bombers/fighters. I usually only use transports and destroyers along with a few battleships for naval combat. I destroy/raze coastal cities with marines so that enemy ships don't have anywhere to go for repairs and bombard my enemy's ships with my destroyers (or artillery and bombers when they get close to my territory). After that, I finish off these damaged, isolated ships with my destroyers/battleships. Do you use carriers often? If so, how do you use them effectively and what are they good for?