Warren Buffett once quipped that a “farsighted capitalist” should have shot down Orville Wright at Kitty Hawk to spare investors all the losses they would suffer on airlines in the decades after the birth of flight. That’s why it was a surprise when, in November, the billionaire’s Berkshire Hathaway Inc. disclosed investments in the four largest U.S. carriers: American Airlines Group Inc., Delta Air Lines Inc., Southwest Airlines Co.