Omaha, we’re ready for takeoff. Warren Buffett’s Berkshire Hathaway Inc. disclosed after the close of trading Monday that it took stakes now worth a combined $1.5 billion in three of the biggest U.S. commercial air carriers: American Airlines Group Inc., Delta Air Lines Inc. and United Continental Holdings Inc. It also added Southwest Airlines Co., according to a CNBC report citing the billionaire. Talk about good timing—they’re all coming off lows of late June and their valuations have been at a larger-than-normal discount to the broader market.  Are Buffett and his investment team betting all those folks who threatened to leave the U.S. in the event of a Donald Trump presidency will start booking flights? OK, maybe not. But it might be that U.S. airlines are finally recovering from a long slide in passenger revenue, which was caused by a glut of flights that squeezed fares.  Scott Kirby, who recently became president of United Continental after leaving American Airlines, said last month that it felt like there had been an “inflection point in domestic revenue,” probably in August. He’s tasked with helping to turn around United (but as Bloomberg’s Michael Sasso has written, the ticket-slashing strategy Kirby employed at American at won’t work for this airline, which needs to get its profit margins on par with rivals). All four companies also recently reported third-quarter profit that beat analysts’ estimates.  Aside from potential tailwinds specific to the airline and travel industries, a Trump administration will probably also embolden carriers to try pushing their agenda with the supposed pro-business president-elect and Republican majority House and Senate. For example, some carriers are pressing Congress to privatize air traffic control.  Credit for these latest Berkshire investments may belong to Todd Combs or Ted Weschler, top investment managers at the $389 billion conglomerate who are behind the very un-Buffett-like stake in Apple Inc. this year. Back in 2001, it was Buffett who said he’d never invest in airlines again after what he called a “mistake” owning US Airways Group:  “Now if I get the urge to invest in airlines, I call an 800 number and I say: Hello, my name is Warren, and I’m an air-o-holic.” Perhaps Buffett wasn’t behind Berkshire’s getting back into the industry. Or perhaps something has convinced him he’s in for a smoother flight this time.  This column does not necessarily reflect the opinion of Bloomberg LP and its owners.