American Airlines says it will use Republic Airways Holdings Inc. to operate regional flights using 76-seat planes.
American announced that it reached a 12-year deal with Republic. The agreement is subject to approval by American's federal bankruptcy court judge.
The move represents a break from American's sister carrier, American Eagle. Both are owned by AMR Corp., which filed for bankruptcy protection in 2011.
Under the agreement, Republic Airlines will get 53 Embraer planes painted in American Eagle colors.
American says the deal will help it to better match plane size to market demand on certain routes.