For the American Airlines' online check-in process, the passenger goes to AA.com and clicks on My Trips/Check-In, as of 2015. He enters his information to look up the reservation, then selects who he's checking in and follows the instructions. After he completes the process, he can print his boarding pass.
As of 2015, online check-in is available 24 hours before the flight's scheduled departure time. The cutoff time for check-in varies depending on the airport and whether the flight is domestic or international.
Information used to look up a reservation includes the passenger's full name and his record locator. Once he has looked up the reservation, he selects the people he's checking in by checking the box next to each passenger's name. After he clicks check-in, he chooses whether he wants to print his boarding pass, receive it via email or receive it on a mobile device. A mobile boarding pass is displayed on the passenger's phone and has a barcode. If the passenger can't retrieve his boarding pass, he can get it at the airport through a self-service kiosk or an American Airlines representative.
The record locator is a reference code that is six characters long. If the passenger doesn't have his record locator, he can log in to his American Airlines account and click on My Reservations to find the reservation.