American Airlines on Monday appealed a U.S. court decision requiring it to end an alliance with JetBlue Airways.

U.S. District Judge Leo Sorokin ruled in May the airlines' "Northeast Alliance" that allowed the two carriers to coordinate flights and pool revenue violated antitrust law.

JetBlue previously said it would not appeal as it seeks to protect a planned $3.8 billion purchase of Spirit Airlines that faces a separate legal challenge from the Justice Department.

(Reporting by David Shepardson; Editing by Chris Reese)