Depending on where you stay in Gahkuch, a free airport shuttle could include 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 Gahkuch. Some hotels have shuttles that run at regular intervals day and night; others require advance reservations for custom departures and pick-ups. Check the hotel's policy on Expedia before booking your stay.