A surge in Thanksgiving demand is taxing Delta's pandemic-era workforce. The carrier was forced to cancel hundreds of flights this week, according to its pilot union and the airline. Delta canceled nearly one in every five flights it was scheduled to operate on Thanksgiving Day, and has dropped in total more than 500 flights this week, even as air travel has been picking up in the last few weeks. The airline said it expects its system to return to normal over the weekend. The Air Line Pilots Association, the union that represents Delta pilots, said staffing reductions due to the coronavirus pandemic and the drop-off in travel "have left a smaller pool of pilots qualified and ready to fly in the fleets that are seeing an increased demand over this holiday." Delta said Wednesday that a "number of factors have pressured our ability to timely staff some of our scheduled holiday flights" but did not specify the issues. After distributing the November employee schedules last month, Delta added flights to its schedule and asked for volunteers to cover those flights, according to a source familiar with the situation. But when there were not enough employees to cover those legs, the airline was forced to cancel some of them. The airline declined to comment on that explanation. The Delta Master Executive Council at the Air Line Pilots Association said its pilots have stepped up to take on extra flights over the holiday period and receive the incentive of premium pay for picking up extra legs. But when demand surged this week, the heavy cuts to the aviation system due to the coronavirus began to show.<br/>