Recently, many passengers have reported that when purchasing tickets and preparing to check in online, a large number of seats are "locked," making it nearly impossible to select more comfortable seats such as those in the front, at the emergency exit, by the window, or on the aisle. Airlines customer service staff stated that the "locked" seats vary by aircraft, and if there are seats available for mileage redemption, it may be attempted to exchange using mileage. If this flight has mileage exchange seats but they are not fully selected, it can also be handled on-site at the airport. Customer service representatives did not provide a clear explanation of the reasons and rules for "locked" seats. According to relevant regulations from several airlines, domestic airlines generally offer a value-added service for pre-selecting seats, international flights usually require payment to purchase, while domestic flights require redemption through accumulated mileage. However, no airline has clearly defined the rules and proportions for "locked" seats. (CCTV News)