American Airlines Group Inc. v. United States

(1) Whether, absent evidence of a marketwide price increase or output reduction, a reduction in competition between two members to a joint venture is sufficient to prove a substantial anticompetitive effect at step one of antitrust law's rule of reason; and (2) whether, to meet its burden at step two of the rule of reason, a defendant must disprove other potential causes for the asserted procompetitive benefits and prove that the asserted procompetitive benefits were not offset by out-of-market anticompetitive effects.