The tracking website Flightaware.com estimates 2,197 flights were cancelled nationwide as of Sunday afternoon. That follows two days of similarly difficult travel conditions.
Cold weather has affected much of the country, but hit Dallas-Fort Worth International Airport particularly hard. The airport said more than 400 departures were cancelled Sunday. It is also still trying to clear out thousands of travellers who have been sleeping at the terminals or in nearby hotels waiting for a flight out since Thursday night.
To ease the pain, the airport has been giving away free coffee, sandwiches and other treats. It also has brought in entertainment to the terminals, including musicians, comedians and balloon artists.
"We are trying to keep the mood light and do everything we can to make sure that our passengers have as good an experience as possible given the situation," airport spokesman David Magana said.
Cold weather turned the region into an "ice rink" Thursday night, he said. That forced 3,000 people to stay the night Thursday, and the figure swelled to 4,000 Friday. As flights began to slowly resume, that figure dropped to 2,000 for Saturday night.
Magana said Sunday is the first day that temperatures will rise above freezing for a few hours, giving staff there a chance to work on improving paved surfaces at the airport.
American Airlines, which has its main hub in Dallas Fort Worth, said it had 1,100 cancellations across its system Sunday. It expects 550 cancellations for Monday, the bulk of which are at the Dallas Fort Worth airport.
The airline has updated its travel policy due to the tough weather, allowing passengers who have trips planned through affected areas to change their flights at no charge to avoid some of the complications.
The problems weren't contained to Texas though.
Delta Air Lines reported delays stretching from the Tennessee Valley to the mid-Atlantic region. The airline estimated it cancelled 20 to 40 flights Sunday.
Philadelphia International Airport spokeswoman Stacey Jackson said there was much more snow and ice than originally anticipated for its area. Initial forecasts of one-half to two inches (1.25 to 5 centimetres) of snow have been upped to four to six inches (10 to 15 centimetres). That led to a temporary ground stop on Sunday, which halted any runway activity until the afternoon.
The airport is also expecting a number of passengers to stay there overnight as area hotels have been full for several days. Jackson said staff will hand out pillows and blankets to make them "feel at home even though they are not."
Airlines and airports alike expect weather-related delays should persist through Monday at least, but may ease later in the week as conditions improve.