The most expensive unit in the game, Carriers provide both support for friendly Air units, as well as Area Denial from enemy Air units.
As its name implies, the Carrier is capable of loading and transporting up to two of any Air unit on deck. Air units loaded on the carrier will have their Fuel and Ammo completely refilled at the beginning of the day. If a Stealth is Hidden when it lands on a Carrier, it will remain hidden when taking off of it, allowing for a relatively safe spot for a Stealth to refuel in combat. As with any unit capable of transporting, if a Carrier is sunk, any aircraft on board is immediately destroyed as well. Extreme care must be taken with Carriers, as losing a loaded Carrier is an extremely expensive loss.
Outside of transporting Air units, the Carrier also functions as an Indirect Combat unit, capable of dealing high damage to enemy Air Units. The amount of damage a Carrier can do is on par with that of Missiles, but with a much larger range, making it a much higher threat to Air units. Unfortunately, due to its very high cost, Carriers are hard to deploy effectively without hindering your economy significantly, and are thus rarely seen units.
Despite being very powerful against Air Units, Carriers are defenseless against Land and Sea units. Land-based Indirect Combat units, Subs, and Battleships all deal high damage to carriers. Air units can also deal considerable damage to Carriers, but with the exception of Hidden Stealths, will have trouble closing the gap effectively. If your opponent builds a Carrier, it is best to immediately capitalize on it and focus on other areas of the map your opponent may be neglecting, as a Carrier is an enormous investment in most situations.
Unless a Carrier is restricting travel of your Air units or is playing a key role in keeping enemy Stealths refueled, Carriers are safe targets to ignore. Due to their cost, however, they may prove effective in giving your CO Power Bar a quick boost if you can damage them somewhat. This is only recommended to do if you can sustain a Power from your opponent, however, as damaging enemy Carriers will fill their Power Bar extremely quickly.