1,200 U.S. flights were canceled Monday as the winter storm hits the east coast

Charlotte Douglas International Airport in North Carolina, en American Airlines (EEL) hub, continues to be hardest hit. More than 400 flights were canceled there on Monday, and 85 delays were reported, according to the flight tracking site FlightAware. The airline preventively canceled 1,100 flights on Sunday across its mainline and regional operations after canceling 90 Saturdays.

"This weekend's winter storm is expected to have a significant impact on our operations, particularly at Charlotte International Airport," American said in a statement. It also issued a travel announcement allowing customers affected by the weather to rebook flights free of charge.

Ronald Reagan Washington National Airport is the second most affected airport, with 38 cancellations reported Monday.

A massive storm system hit the eastern United States and the Midwest over the weekend. There were reports of paralyzing ice in parts of Georgia, Virginia and Carolina on Sunday. The governors of these states have declared emergencies.

Monday is Martin Luther King, Jr., day, a federal holiday, and many schools and offices were closed.

American is not the only airline canceling flights. From kl. 8.00 ET Monday, Southwest (LUV) canceled 72 flights, according to FlightAware, while Delta Air Lines (FROM) canceled 37 flights. JetBlue (JBLU) canceled 49 flights and 82 flights on United (UAL) has been cut off.

It has been some miserable weeks being an air traveler. Winter weather and Omicron hikes caused 20,000 U.S. flights to be canceled during the busy holiday travel season. As travel increased, staff cuts also left airlines with fewer employees than they had before the pandemic.

--CNN Business' Ramishah Maruf contributed to this report.

CNN's Jason Hanna, Hannah Gard, Alanne Orjoux and Chris Isidore contributed to this report.