Few expected 17% to be the new norm. That was the U.S. airline industry’s collective operating margin for all of 2015, when just about everything was going right, most importantly extremely low fuel prices, solid demand and conservative capacity and pricing policies still mostly in place from before the onset of cheap oil. Margins seemed bound to fall from such lofty heights, and so they did in 2016, but only ever so slightly to 16% —this alarmed no one.
