More than 1,600 US flights were canceled on Wednesday amid winter storms.
Nearly 5,000 US flights were delayed as of Wednesday evening.
Winter storms are battering portions of the Midwest and Northeast.
California is bracing for another round of strong winter storms with gusty winds.
A rare blizzard warning was issued for Los Angeles on Wednesday.
NBC News reported:
More than 1,500 flights within, to and out of the United States were canceled Wednesday as severe weather wreaked havoc with massive storms threatening to bring record snowfall across America.
Residents across the northern Plains will be hunkering down as the storm hits, with schools across the Dakotas, Minnesota and Wisconsin announcing closures ahead of the severe weather system, which is expected to affect millions while California contends with strong winds and sweeping power outages.
The National Weather Service issued winter storm, blizzard and high-wind advisories for swaths of the western and the north-central U.S., with up to 2 feet of snow expected in some areas through Thursday.
At least 4,728 flights, within, into or out of the United States, had been delayed by late Wednesday afternoon, according to the online flight tracker FlightAware.
There were 1,556 U.S. flight cancellations by 6 p.m. EST, and at least 425 of those called-off journeys were related to Minneapolis-St. Paul International Airport. At least 270 cancellations were listed out of or into Denver International Airport.