For air travelers, the new year picked up where the old one left off — with lots of frustration.

By late Saturday afternoon on the East Coast, more than 2,600 U.S. flights and nearly 4,600 worldwide had been canceled.

That is the highest single-day U.S. toll yet since just before Christmas, when airlines began blaming staffing shortages on increasing COVID-19 infections among crews. More than 12,000 U.S. flights have been canceled since Dec. 24.

Saturday’s disruptions weren’t just due to the virus, however. Wintry weather made Chicago the worst place in the country for travelers. More than 800 flights were scrubbed at O’Hare Airport.