It's an incentive to pack light. American Airlines says fliers with less carry-on baggage get to board earlier.
Beginning Thursday, customers who don't need to use the overhead storage bins will get to board in the first few groups.
Passengers who get to the gate and decide they want to take advantage of the perk will be able to check-in their bag at no charge.
American Airlines said it successfully tested the process at seven airports earlier this year.
The airline said the new system saves overall boarding time.