The first quarter of 2016 was another supremely profitable one for U.S. airlines, which walked away with almost $3.4b in net profits, with an unthinkably high 16% operating margin—this during what is generally the most off-peak period of the year. Underneath the surface, however, were some uncomfortable trends, led by revenue weakness that seems to be increasing in severity. At the same time, fuel prices, although still extremely low by the standards of the past decade, are in fact rising steadily—after dipping below $30 a barrel in February, oil prices are now flirting with the $50 mark. Labor costs, meanwhile,…
