With check-in chicken, travelers will intentionally delay their online check-in to the last minute in hopes of a better seat. The method relies on the fact that airlines will often charge extra for better seats, split up groups and initially assign fewer desirable seats.

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

United Airlines is shaking up its check-in policy, and if you're a domestic traveler, you'll want to pay attention.