American Will Challenge Ruling That Blocked JetBlue Alliance (1)

American Airlines Group Inc. plans to appeal a federal judge’s ruling that its operating alliance with JetBlue Airways Corp. violates antitrust laws and must be dismantled.

The partnership, known as the Northeast Alliance, has provided consumer benefits and strengthened competition with other airlines, American Chief Executive Officer Robert Isom said Wednesday at an industry conference in New York.

“I, quite frankly, disagree with the ruling,” he said. “We’ve got a legal system that allows for appeal and we’re going to do that.”

The ruling this month to shut down the partnership was a blow for the carriers, which have criticized ...