American Airlines is testing a new system to make sure travelers board with their designated groups.

The airline, which is using an audible sound to signify if travelers try to board too early, is testing the new system at both the Albuquerque International Sunport airport (ABQ) and the Tucson International Airport (TUS), American Airlines shared with Travel + Leisure. The carrier plans to expand the test to other locations soon, including to Ronald Reagan Washington National Airport (DCA).

“We are in the early phase of testing new technology used during the boarding process,” an American Airlines spokesperson said in a statement shared with T+L. “The new technology is designed to ensure customers receive the benefits of priority boarding with ease and helps improve the boarding experience by providing greater visibility into boarding progress for our team.”

As part of the test, travelers who try to board too early will hear a sound when they scan their boarding pass. The airline said it has been pleased with the results of the test so far.

American Airlines is not the only airline to switch up how it boards its planes. Last year, United Airlines updated its boarding procedure to allow travelers in window and middle seats to board earlier in an effort to speed up the process; and earlier this year, Delta Air Lines changed how it classifies boarding zones, switching to a number-based system.

Next year, Southwest Airlines plans to nix its own open seating and instead use assigned seats to board its aircraft.

Of course, it's understandable why travelers would prefer to board planes early since the earlier you get on, the more likely you are to have overhead bin space for your carry-on (especially on full flights). One of the most sure-fire ways to ensure you board first is to sign up for a frequent flier program and earn status on a specific airline since carriers typically reward their most loyal customers with priority boarding, among other perks.