Delta Air Lines closed the books on a disastrous 2020 with a comparatively small fourth-quarter loss, and executives expect a few more rocky months before — they hope — widespread coronavirus vaccinations and testing might salvage something of the upcoming summer travel season. Delta on Thursday reported a quarterly loss of $755m and $12.4bn in losses for all of 2020. It is the largest annual loss in the history of the airline, which dates to the 1920s, and the global pandemic ended a decade in which Delta churned out a profit each and every year. The fourth-quarter numbers likely would have been worse but for a December increase in air travel that likely contributed to another surge in virus infections as millions crossed the United States to spend time with family and friends during the holidays.