"In Charlotte, we have cut down roughly half of our 640 departures," Mohr said. "We have other cancellations throughout the system, in anticipation of the weather."
The goal was to cancel flights before customers arrived at the airport.
Southwest Airlines ran normal operations Wednesday in Philadelphia, but suspended flights Thursday through 4 p.m., said airline spokesman Dan Landson. Southwest normally operates 30 flights a day to 12 cities from Philadelphia.
American and US Airways canceled approximately 75 departures and arrivals Wednesday that impacted Philadelphia International Airport "due to weather along the East Coast," said American spokesman Matt Miller. Systemwide, American has canceled more than 200 flights, Miller said.
Roughly half of US Airways flights in Philadelphia, Washington, and New York will not operate Thursday, including the Philadelphia-Tel Aviv, Israel, flight Wednesday night and the inbound Tel Aviv flight Thursday.
"We will be reducing operations by about 50 percent on Thursday at Philadelphia, Washington, D.C., National, and LaGuardia airports," Mohr said.
Airlines were thinning out their schedules in anticipation of the storm, said Philadelphia International spokeswoman Victoria Lupica. "Everyone is planning and communicating with their passengers," she said.
Total U.S. flight cancellations were 3,271 Wednesday, according to flight-tracking website FlightAware.com. Delays totaled 2,207.
Delta Air Lines, with a hub in Atlanta, canceled 1,700 flights systemwide Wednesday due to icy precipitation. Many, if not all flights, to Atlanta from Philadelphia were canceled, an airline spokesman said.
Airlines have waived cancellation and change fees for travel on or before Feb. 17 to Feb. 19, depending on the carrier.
"Crews are going to be mobilized, clearing the runways as soon as there is something to clear," Lupica said. "We are making sure the equipment, any chemicals, salt for the roadways, personnel, that everything is in place."
"Air travel Thursday morning we should expect to be delayed or canceled, depending on the weather," Lupica said. The sooner the storm changes over to rain, the less snow will accumulate. "Many airlines, if not all, are being very considerate with change fees."