NEW YORK (AP) — Airlines canceled hundreds of flights Saturday as staffing issues tied to COVID-19 disrupted holiday celebrations during one of the busiest travel times of the year. FlightAware, a flight-tracking website, notes 875 flights entering, leaving or inside the U.S. canceled Saturday, up from 689 Friday. About 200 more flights were already canceled for Sunday. FlightAware does not say why flights are canceled. Delta, United and JetBlue on Friday had all said the omicron variant was causing staffing problems leading to flight cancellations. Flight delays and cancellations tied to staffing shortages have been a regular problem for the U.S. airline industry this year.