Fuel historically accounts for about one-third of industry operating costs. Rob Britton, who spent two decades with American Airlines Group Inc., is unapologetic in defending the profits his former employer and other U.S. carriers are making. Sure, fuel’s cheap, but what company cuts prices as soon as its costs shrink? “Amtrak doesn’t lower its prices because diesel is cheaper, and New York taxi cabs don’t lower their prices because a tank of gas is cheaper,” said Britton, now an aviation consultant in Washington. Consumers have benefited somewhat from the lowest jet-fuel costs in more than 12 years, but not nearly as much as the companies. While travelers are paying less on average for trips, base fares — the prices assigned to each seat — have remained essentially unchanged since 2014, according to Rick Seaney, chief executive officer of ticket-research company FareCompare.com. Meanwhile, spot jet-fuel prices in New York harbor […]