How fast can I buy the train ticket to laojie and can i buy a return ticket back to airport?

Shuttling by metro is fast and you can buy ticket fast in the metro station. As I know, no return ticket is available, so buy that for two ways. And here is the way to go:
take line 11 to Chegongmiao and change to line 1 to Laojie. It is the same for the return trip.