Starting on Tuesday, June 3, United will require all domestic travelers to check in at least 45 minutes before departure. That's 15 minutes earlier than the previous 30-minute cut-off for passengers without checked bags.
With the new policy, late check-ins could mean losing your seat or your luggage.
"If you don't meet your check-in time limits, we'll do our best to find another option," United said on its website. "However, we have the right to deny service which may result in cancellation of your reservation, denied boarding or the option to check your bags."
International travelers still need to check in 60 minutes before departure. Certain cities, like Honolulu, have airports with special check-in time limits.
Most airlines already suggest getting to an airport at least two hours before domestic flights and three hours prior to international departures.
"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," a United spokesperson told USA Today in a statement.
United says it flies about 140 million people to more than 300 destinations worldwide each year.
Click here to follow Daily Voice Rutherford and receive free news updates.