+1-844-414-9223  For more information on American Airlines check-in as well as other relevant details, please refer to this blog from TheAirlinesInfo. To make a flight check-in: As early as 24 hours before your first flight's departure, visit your airline's website. Use your online account's confirmation number to check-in. Additionally, you will be able to confirm your seating options and view your seats, provided the airlines enable it.