While it is not strictly mandatory to select a seat when booking an international flight in 2026, it is highly recommended if you have specific preferences or are traveling with others. If you choose not to pay for a seat selection during the booking process, the airline will automatically assign you a seat during the check-in window (usually 24 to 48 hours before departure). For solo travelers on a budget, skipping the fee and waiting for the auto-assignment is a common way to save $30–$100. However, on ultra-long-haul flights, the risk of being assigned a middle seat near the lavatories is high if the flight is full. If you are traveling as a family or a group on a single reservation, most full-service carriers will attempt to seat you together, but they do not guarantee it without a paid selection. For the best experience, checking in the exact minute the window opens can often allow you to pick from the remaining "free" seats before they are all taken by other passengers.