Depending on where you stay in Antadao, a free airport shuttle might be a two-way trip to and from the airport, at certain hours of the day, or it could be just a one-way trip to the airport.
How often will the shuttle run?
It depends on the hotel you choose to stay in Antadao. A courtesy shuttle to and from the airport may run 24/7 or it could be restricted to certain times a day. It's important to check the hotel's policy on Expedia before you book.