NEW YORK (AP) — American travelers flying with United Airlines will have to check in to domestic flights a little earlier starting next week. That is, if they’re customers only taking carry-on bags.

Effective June 3, United’s “check-in cutoff” for most flights will be 45 minutes before departure. That’s the same deadline United has for passengers checking luggage at the airport but 15 minutes earlier than the current one for people without bags to check.

In an email to The Associated Press, a United spokesperson said the change to a single cut-off minimum “brings greater consistency for our customers” and conforms with the policies of many other airlines.

Checking in for a flight confirms a passenger’s booking and intent to travel ahead of takeoff. Most major carriers have online check-in systems that can be used at least 24 hours in advance, so the process no longer reflects when many travelers arrive at the airport. Yet it’s still an important step since boarding passes are issued once check-ins are completed.

Other United States and international carriers have tightened their check-in and boarding policies as part of strategies for maintaining on-time departures, particularly amid the high demand that followed the COVID-19 pandemic.

Generally speaking, checking in allows airports and airlines to prepare for upcoming flights, from confirming seat assignments to making sure passenger names are at the security checkpoint. Check-in cutoffs, or the latest possible time to claim a flight reservation, are typically earlier for international flights to account for the time needed to check passports and clear customs.

Requirements may vary by airline and airport. Emirates, for example, closes online check-ins 90 minutes before departure. Ireland’s Ryanair allows online check-in up to two hours before a flight; passengers still may check in at the airport 40 minutes in advance, but for a fee.

While the new cutoff applies to most of United’s domestic trips, check-in deadlines may vary by location and route. The carrier’s website notes that St. Thomas’ airport in the U.S. Virgin Islands has a check-in time limit of 90 minutes prior to departure, the same cutoff listed for flights between Guam and Honolulu.

For international flights, United requires checking in at least an hour before departure. Many airports have earlier deadlines, such as 75 minutes for major airports in Paris and Dubai, and 90 minutes for the airports in Toronto and Lagos, Nigeria.