Airlines end a strong summer, but the Delta variant stifles momentum.

Airlines ended the traditional summer travel season on a high note, but hopes for the fall have dimmed as employers delay office reopenings and the Delta variant of the coronavirus has eroded sales and driven up cancellations in recent weeks. United said in a securities filing on Thursday that it no longer expected to turn a profit, before taxes, for the three months ending in September and that revenue would probably be down about a third from the same period in 2019. Nevertheless, the airline said it expected to reap previously predicted cost savings. Delta appeared to be in a stronger position. The airline said in a filing that it still expected a pretax profit for the quarter, but that revenue would probably be at the lower end of a forecast it made earlier this summer. Costs were at the higher end of expectations as Delta staffed up to keep operations running smoothly through the rebound. “The story for the quarter really has been about the amazing surge in demand that we’ve witnessed,” Ed Bastian, Delta’s CE, said at a Thursday conference hosted by Cowen, an investment bank. Both United and Delta said they expected to see the recovery resume once virus cases peaked, with Bastian adding that the airline was already seeing a rebound in the South, where infections began rising sharply in the summer. United and Southwest Airlines said in filings that the latest wave of infections had less of an effect on the business than previous jumps in coronavirus cases.<br/>