Airlines have benefited from years of restructuring and consolidation, a tighter focus by management on profitability, and a roughly 55% drop since mid-2014 in the price of oil, which has gone from the industry’s biggest cost to its second biggest after labor. Planes are also fuller than ever. Airlines for America, a trade group, has predicted an all-time high for summer travel, and this week forecast 14.2 million passengers will fly over the Labor Day period, up 3% from a year ago. The busiest day is expected to be Friday, Sept. 4. However, it is what passengers are spending on fares and extras that is spooking investors. Get the full story at iBloomberg