Starting June 3, domestic United Airlines passengers without checked bags will need to check in 45 minutes before their flight. The time limit was previously 30 minutes. United’s domestic customers with checked bags must also check in 45 minutes before takeoff, a continuation of the previous policy. All international travelers must check in 60 minutes before their flight.
United implemented the policy to streamline operations

According to United, its revised domestic check-in policy is designed to enhance efficiency and streamline its process. With the additional time, agents can better assist on-time passengers with luggage, boarding, and arrangements. As of Tuesday, June 3, the airline will stick to the rule without exceptions. United passengers can check in online, via the United app, or at the airport. Though some may disapprove of the change, checking in early and arriving two hours before takeoff is a good rule of thumb.
Many airlines recommend arriving at the terminal two hours before departure, and Lisa Farbstein, a Transportation Security Administration spokesperson, concurs. She told Travel + Leisure, “We recommend that when flying domestically out of a medium to large airport that travelers get to the checkpoint two hours prior to their airline departure time, regardless of whether they are enrolled in TSA PreCheck. This is especially important if someone is traveling during a holiday period.”
The two-hour rule makes sense when you consider possible traffic, parking delays, busy ticket counters, or holiday periods. Having a nice pre-flight cushion provides peace of mind, as well as time to explore shops and restaurants, or simply catch up on the latest news. Those flying internationally are advised to arrive at the terminal three hours prior, which helps account for a longer boarding process (45 minutes to an hour) due to larger airplanes.