American Airlines is implementing new technology to prevent travelers from boarding before their designated group is called. The system uses a two-note sound to deny access and is currently active in over 100 U.S. airports. The airline expects over 8 million passengers during the Thanksgiving travel period, up nearly half a million from last year. The new technology is now active in over 100 non-hub airports across the U.S. after successful testing over the past month. American Airlines plans to expand the system to its hubs.