United Airlines check-in counters at international locations, including Chengdu, generally open three hours before a scheduled flight's departure. For travelers departing from Chengdu Tianfu International Airport (TFU), it is highly recommended to arrive at least three hours before an international flight to allow sufficient time for the check-in process, security screenings, and immigration. Please note that check-in and bag drop counters typically close 60 minutes prior to the scheduled departure time. Since operating hours can vary based on specific flight schedules and airport policies, passengers should verify the status of their flight and the exact counter opening times directly with United Airlines before traveling.