What is the best way to move a cat from Shanghai to Shenzhen?

We will be moving from Shanghai to Shenzhen in September. We will be back in the USA in between. We have a cat which we will leave with friends but are wondering how to move it to Shenzhen? (plane? train?)Can it be sent somehow alone or will we need to return to Shanghai to get it and bring it back? Does it need vaccinations to make this trip?