You can technically "no-show" for a flight, but it carries significant consequences for your itinerary. The moment you miss your outbound flight without notifying the airline, their automated systems will typically cancel all remaining segments of your trip, including your return flight, with no refund. This is known as the "no-show policy" designed to prevent "hidden city ticketing." If you simply cannot make it, it is much better to cancel or change the flight via the app at least a few hours before departure; even if the ticket is non-refundable, you may receive a Future Flight Credit (minus a change fee) instead of losing the entire value. Additionally, if you are a frequent flyer, repeated no-shows can lead to an airline flagging your account or even revoking your loyalty points. If you are at the airport and decide not to board, be sure to inform a gate agent so they can remove your name and avoid delaying the flight while they search for a "missing" passenger.