There is no cost to join the American Airlines AAdvantage program. Membership is free and open to anyone who wants to join. Once you are a member, you can start earning miles by flying with American Airlines or any of its partner airlines, using an American Airlines co-branded credit card, staying at participating hotels, or renting a car from participating agencies. You can then redeem your miles for a variety of award options, such as flights, hotel stays, car rentals, and other travel-related experiences.