Loool China is welcome to do it if it can/has the capabilities to do so(which it doesn't have for now, it needs at least a decade or two to even come close to having such capabilities), until then the U.S is very much justified in carrying out its spy/military patrol in international airspace close to China. China can only come as close as Hawaii/Guam if at all, not U.S mainland.
You don't have to cry for others strength, you should cry for your own weakness. Just like an Indian member here said, China can only bully/do what the U.S is doing now to weaker countries like India, Philippines, Vietnam etc. It should also know how it feels to be powerless/weaker when faced with a tougher/more powerful adversary .