By DAVID McHUGH and TALI ARBEL
NEW YORK (AP) — Airlines are canceling hundreds of flights as the omicron variant jumbled schedules and drew down staffing levels at some carriers during the busy holiday travel season. Delta Air Lines and United Airlines together canceled more than 600 flights on Friday and Saturday, while other airlines say operations are proceeding normally. Flight delays and cancellations tied to staffing shortages have been a regular problem for the U.S. airline industry this year as travel recovered. While some travelers canceled holiday plans because of rising case numbers, many others kept to their vacations during some of the year’s busiest travel days.