Other airlines reported delays averaging an hour.
In some areas, public schools called off classes; state workers were sent home; and flights were canceled. With a polar vortex hitting the Midwest, wind chills could dip to 55 degrees below zero in northern IL. Michigan Gov. Gretchen Whitmer is encouraging motorists to stay off the roads.
In Wisconsin's biggest city, Milwaukee, downtown streets were virtually deserted Monday and every major highway in the state covered in ice or snow, according to the Milwaukee Journal Sentinel.
A winter storm brought more than 5 inches of snow to northern IL as the region braced itself for record-low subzero temperatures.
A winter storm system bringing blizzard-like conditions across the Upper Midwest on Monday will dump wintry weather across parts of the Deep South and Northeast by midweek, creating treacherous travel conditions. Rain could begin to mix in during the afternoon.
Around Baltimore, lows early Wednesday morning are forecast in the lower 20s, with wind chills in the teens, and temperatures are expected to top out only in the upper 20s Wednesday afternoon.
On Sunday, International Falls, Minnesota tumbled to -46°F (-43°C), the fifth lowest temperature it has ever recorded.
The wind chill in the Charlotte region could be around 17 degrees as the front passes through, says the National Weather Service. "The heaviest snow is expected in our MI counties where 6-9" of snow is possible.
In Wisconsin, plow drivers were having a hard time keeping up with the snow in Sheboygan. And then an even colder front is forecast to pass through Wednesday, ushering in bitterly cold air across the Great Lakes and Northeast.
More than a foot (30.5 centimeters) of snow was expected to accumulate Monday in southeastern Wisconsin and southeastern Minnesota.
In eastern North Dakota, officials have issued travel alerts because of blowing snow.
It warned frostbite can occur to exposed skin within minutes under such conditions.
Another formidable bout of snowfall is heading to the Chicago area Sunday night, possibly dumping 4 to 7 inches of snow before temperatures are expected to plummet to risky levels the region hasn't seen in years. The record low for January 30 (Wednesday) in Normal was 15 below zero, recorded in 1966, according to the National Weather Service.