United States v. AMR Corp.

American Airlines (defendant) temporarily lowered prices and increased flight capacity at its Dallas Fort Worth hub to compete with low-cost carriers, then returned to prior pricing levels once those carriers left the market; the United States (plaintiff) sued alleging monopolization and attempted monopolization under Sherman Act § 2, using four proposed tests to show American's pricing created a net economic loss, but American argued it never priced below its average variable cost, and the district court granted American summary judgment.