Passengers traveling without checked baggage on United Airlines should know the cutoff time for check-in will change as of June 3.

According to the airline, the check-in cutoff time for domestic flights will change from 30 minutes before departure to 45 minutes before departure for passengers who do not need to check any luggage.

"The change brings greater consistency for our customers by aligning with our current checked baggage deadline and the check-in policies followed by most other airlines," United said in part in a statement.

The check-in process remains the same.

Millions of people hit the road and packed airports over Memorial Day weekend, largely considered the unofficial start of summer. Airlines reported a 5% increase in air travel compared to 2024 heading into the weekend, and many expected the highest volume of travelers on Monday.

The Federal Aviation Administration expected record-high travel over the holiday weekend and its busiest summer in 15 years, with the peak at the end of July. The agency has said it's prepared for the high volume, but travel industry experts warn that understaffing and infrastructure breakdowns could complicate operations.

There are plans in the works from the Department of Transportation and the FAA to address these issues at airports and air traffic control facilities, but a complete revamp of the air traffic control system will take at least the next three to four years.

This is also the first summer travel season under the new Real ID requirements. If you don't have a Real ID for domestic travel, you can use other forms of compliant ID — like a passport, passport card or Global Entry card — to get through TSA checkpoints at airports. 

In April, Delta Airlines announced a similar change in its policies, requiring all customers checking a bag to do so at least 45 minutes before scheduled departure for all domestic flights, with a few exceptions. 

CBS News' Kathryn Krupnik and CNN contributed to this report.