Some major U.S. airlines including Delta and Southwest are rushing to finance losing bets on oil and revamp fuel hedges as tumbling crude prices leave them with billions of dollars in losses, according to people familiar with the hedging schemes. In theory, airlines are among the top beneficiaries of a six-month slump that halved crude prices to five-year lows. Oil is the biggest variable cost for airlines, often representing a third or more of their total operating expenses. But now, carriers such as Delta Air Lines and even Southwest Airlines, known for a successful hedging program that locked in cheap fuel prices before they rose a decade ago, see some of the benefits of cheap fuel eaten away by hedging costs. That is largely because they have used common but risky hedging strategies, among them a “costless collar”: selling financial options that pay off when […]