American Airlines will expand its new boarding alert system to more than 100 airports across the U.S. before Thanksgiving. Among those airports will be Austin-Bergstrom and Atlanta. 

The carrier’s hubs, as well as more airports, will get the technology in the coming months. 

The system emits a beep when customers attempt to board a flight before they are supposed to. A gate agent will then ask the flyer to step aside until the correct boarding group is called. It was trialed in Albuquerque, Tucson and Washington Reagan ahead of the upcoming broader rollout. 

“We’ve heard from our customers that the ability to board with their assigned group is important to them because it’s a benefit associated with their AAdvantage status or fare purchase,” said Julie Rath, American’s senior vice president of airport operations, reservations and service recovery. “The initial positive response from customers and team members has exceeded our expectations.”

American boards its aircraft in 10 phases, starting with its highest-level AAdvantage status members, then working its way through members of U.S. armed forces, flyers with premium seats, lower-level status customers and American co-branded credit card holders. 

The late-boarding groups are for economy customers who aren’t AAdvantage members and for basic economy flyers.

American passengers often pay extra to board early, either through the purchase of a premium seat or through the direct purchase of priority boarding. Increased policing of the boarding process protects the value of that perk.