American-JetBlue Alliance Meets Critical First Circuit Judges

American Airlines Group Inc.'s now-dismantled alliance with JetBlue Airways Corp. remains in jeopardy after a panel of First Circuit judges signaled potential agreement with a lower court’s decision to end it.

The appeals court’s ruling could advance legal precedent around the antitrust analysis of joint ventures, where two or more parties work together to accomplish a shared outcome. American argues that adopting the lower court’s reasoning would call nearly any joint venture into question on antitrust grounds.

The district court found a number of anticompetitive effects associated with the alliance, including “decreased capacity, lower frequencies, and reduced consumer choice” related ...