I use aircraft carriers when I am playing on a large map with lots and islands and continents and lots of ocean. If the civ I'm at war with is at a great distance from me, I send a naval/air conquest. My destroyers, AEGIS cruisers, battleships, etc. go ahead and behind the aircraft carriers and transports (loaded with marines and perhaps some spies) to guard them and I move them together towards my enemy's cities. When the first wave of my navy arrives, they take out the units in the enemy coastal cities. Next my transport(s) and aircraft carrier(s) arrive. The transport brings marines to the cities where I've knocked off all the defense with my first wave of naval vessels. They take over those cities. Of course, this produces many enemy partisans at times. This is where the stlth fighters (and sometimes helicopters; I don't use them often...too vulnerable) and spies come in handy. I bribe as many partisans as I can and leave the rest to my stlth fighters (if any partisans are left) and when I'm finished I move both spies and the slth fighters into the cities I've taken over. Then, I use my stlth fighters to destroy all the units in the inland cities and let my land units take over the empty cities. I find I lose a heck of a lot less units this way. When partisans pop up around inland cities, I use spies or stlth fighters. I can sometimes take 6 or more cities in one turn using this method with little or no resistence and casualties. Of course, if a city has a coastal fortress or sam missle battery to hinder my naval and air attacks, my spy goes to work immediately to rid the city of such improvements. The only thing with this strategy is that you have to be extremely coordinated with the naval and air movements and this can take lots of practice, at least it did with me, but once you've mastered it (I still don't do it perfect ALL the time, but most of the time) it works wonderfully in conquest.
