the Chinese have been trying to build a carrier for 3 decades and haven't even managed to refit the old "Varyag". They lack the ships to form a Battle Group and at the rate they are building its unlikely they'll have enough by 2020
A single Chinese carrier is only useful IF the USN aren't on the scene and you can go and make threatening noises in the S China Sea and hope someone hasn't reversed engineered your own anti ship missiles or bought something from Moscow