Aircraft Carrier Useless???

When planes run low on fuel/juice/whatever it is, they end up flying much slower and therefore being much more vulnerable to AA/interceptors. Yes they could fly all the way back to a base and repair/refuel/rearm, however they'll still take quite a bit of time to accomplish that. A carrier sitting offshore or in the sky nearby will allow you to keep up a constant amount of pressure on the enemy and not have to have gaps of time spent flying all the way back to base.

For the people saying the Atlantis is useless, I have to wonder if they've even tried the unit out. It's a monstrous sub that is armed with alot of AA weaponry and it can annihilate enemy aircraft quite easily. On top of that it can dive to escape alot of enemy fire. Finally it launches a powerful spread of torpedoes that can destroy naval units rather efficiently. I did a test where I had the Atlantis go up against the tempest (both submerged) and the Atlantis beat it rather easily, even more impressive due to the fact that the Tempest started firing long before the Atlantis did and the Tempest is supposed to be more of a combat unit than the Atlantis.