Stragglers beware: U.S. travelers flying with United Airlines will have to check in to domestic flights a little earlier starting next week. Effective June 3, United's “check-in cutoff” for most U.S. flights will be 45 minutes before departure. 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.