American Airlines' conditions specifically prohibit “purchasing a ticket without intending to fly all flights to gain lower fares (hidden city ticketing).” Most other major U.S. airlines have similar restrictions in place.

American Airlines has a very strict policy prohibiting "hidden city" ticketing, which is the practice of booking a flight with a layover in your intended destination and then intentionally skipping the second leg of the journey because it was cheaper than booking a direct flight. According to the American Airlines "Conditions of Carriage," this is considered a violation of the fare rules. If the airline detects that you have skipped a segment of your journey, they reserve the right to cancel the remainder of your itinerary (including your return flight) without a refund. Furthermore, they may strip you of your AAdvantage frequent flyer miles, revoke your elite status, or even ban you from flying with the airline in the future. American has recently increased its use of automated "auditing" software to flag passengers who don't show up for their connecting flights. Because your bags are always checked to the final destination on the ticket, hidden city ticketing is only possible if you are traveling with carry-on luggage only. While not "illegal" in a criminal sense, it is a breach of contract that can lead to significant financial loss and long-term travel restrictions if you are caught by the airline's security team.