No, it is not illegal to use Skiplagged or the practice of "hidden-city ticketing" (booking a flight with a layover and exiting at the layover city), but it is a significant violation of an airline's Contract of Carriage. When you buy a ticket, you agree to the airline's terms, which state that you must complete all segments of the journey. While you won't face criminal charges or go to jail, the consequences are strictly civil and contractual. Airlines have been known to void frequent flyer miles, close loyalty accounts, and even ban passengers who habitually use this tactic. Furthermore, if you "skiplag," you cannot check a bag, as it will be sent to the final ticketed destination, and if the flight is rerouted due to weather, the airline is only obligated to get you to the final city on your ticket, not your intended layover. In 2026, airlines use advanced software to track "no-shows" on second legs; while doing it once may go unnoticed, a pattern of skiplagging will likely result in a "nastygram" from the airline's legal department or a demand for the fare difference.