An unusual blast of snow and ice in the South added to the nation's travel woes Wednesday, this time with Atlanta topping the misery map.
Atlanta's Hartsfield-Jackson International (KATL) had canceled 301 flights by 9 a.m. EST, a total of 25 percent of its flights. All in-bound flights had been held at their origin airports until 10 a.m., according to flightaware.com.
"KATL is the most weather impacted airport today, but it is still a vast improvement over their cancellations yesterday," Andrew Taylor, an aviation support specialist at flightaware, said in an email to CNBC.
Dozens of flights were also canceled at Chicago O'Hare, Houston Bush International, Cleveland-Hopkins, New York's LaGuardia and in Charlotte and Raleigh-Durham. N.C., Norfolk, Va.
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As of 10 a.m., nearly 1,800 flights had been canceled and more than 4,300 had been delayed, according to flightaware.com.
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At 9:45 a.m. the official Twitter account for the New Orleans airport tweeted its first flight was en route, but warned that public transportation was not yet running due to hazardous roads.
Icy and snowy roads were a problem across the region, stranding schoolchildren overnight on school buses in Birmingham, Ala., and Marietta, Ga.
Megabus said it was canceling all of its Wednesday service to and from Atlanta along with all southbound routes from Washington, D.C.
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Amtrak said it expected to resume a full schedule of trains to and from Chicago after reducing service Tuesday due to the weather.
The airlines expect to take a financial hit as a result of the chain of January storms. JetBlue on Wednesday said its first-quarter total revenue results will be reduced by an estimated $45 million and operating income will be reduced by about $30 million for the same reason. Severe weather led the airline to cancel 1,800 flights earlier this month, the company said as part of its announcement of record fourth-quarter earnings.
The Flight Aware Misery Map showed a number of problems across the United States. Those cancellations appeared to be all weather related, Taylor told CNBC. A job action from a European flight attendants union appeared to not be a factor, he said.
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—By CNBC's Amy Langfield. Follow her on Twitter at @AmyLangfield.
Follow Road Warrior on Twitter at @CNBCtravel.