Whether United Airlines makes you pay for seat selection depends entirely on your fare class and elite status. If you book a Basic Economy ticket, you do not get to pick a seat for free; one will be assigned to you at check-in, and if you want to choose in advance, you must pay a fee starting at $15 per flight. For standard Economy tickets, you can select "Standard" seats for free at the time of booking, but you must pay for "Preferred" seats (standard seats in better locations) or "Economy Plus" (extra legroom). In 2026, United's "Preferred" seats usually start around $24. However, if you are a United MileagePlus Premier member (Silver or higher), you get complimentary access to Economy Plus and Preferred seating. A 2026 "insider tip" is that if you don't pay for a seat in Basic Economy, the system will often place you in a middle seat, so paying the fee is often the only way to guarantee a window or aisle.