Selling American Airlines AAdvantage miles is not "illegal" in the sense of criminal law (you won't go to jail), but it is a major violation of the airline's Terms and Conditions. American Airlines explicitly states that miles do not belong to the member and have no cash value; they are the property of the airline. If the airline's "Revenue Integrity" or fraud department detects that you have sold miles—often by monitoring third-party "mileage broker" websites—they have the right to permanently terminate your account, confiscate all remaining miles, and cancel any outstanding award tickets booked with those miles. In some cases, passengers traveling on tickets purchased from a broker may be stranded at the airport or forced to buy a full-fare ticket on the spot. While there is no federal law in the U.S. prohibiting the sale of loyalty points, the contractual consequences are severe. Instead of selling, American Airlines provides legal ways to share miles through their official "Gift or Transfer" portal, though these options usually involve a fee and are intended for friends and family.