Boiled by Oil: For U.S. airlines, profits are falling even at a time of epic demand strength

It takes a long time to descend from a high mountain. But U.S. airline profitability is indeed descending, still strong relative to the global average but getting further away from its peak. During the springtime April-to-June quarter, the sector’s nine major publicly-traded airlines collectively earned a 13% operating margin, down from close to 18% in the same period a year earlier. Here’s an explanation of why exactly the decline occurred, and what’s behind other major trends and developments that transpired during the quarter.