Thousands of flights have been either delayed or canceled around the United States as a winter storm hits the East Coast on the holiday weekend.

According to Flightaware, 4,910 flights worldwide have been canceled, 2,962 of those are either in or out of the U.S. or within the U.S.

American Airlines canceled 658 flights or 22% of its operation.

Last week, the airline issued a travel alert allowing customers whose travel plans may be impacted by this inclement weather to rebook flights without a fee.

American isn’t the only carrier canceling flights. As of Sunday afternoon, Southwest canceled 343 flights, or 10% of its operation, while Delta Air Lines canceled 244 flights or 11% of its operation.