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