Flight cancellations piled up at hubs such as New York's LaGuardia Airport, Philadelphia and Newark, and by midday Wednesday around 250 flights had been canceled, according to the tracking website FlightAware.com.
But that was a tiny fraction of the nearly 32,000 flights that were scheduled to, from or within the U.S. on Wednesday, the site said.
And the weather in many places was improving as the day went on.
High winds could prevent giant balloons from taking flight this year at the Macy's Thanksgiving parade on Thursday. Safety rules that specify wind speeds were enacted after a spectator was killed in 1997 in an accident involving an out-of-control balloon.
The storm, which developed in the West over the weekend, has been blamed for at least 12 deaths, five of them in Texas.
But as it moved east, it wasn't as bad as feared.
''This is a fairly typical storm for this time of year,'' said Chris Vaccaro of the National Weather Service. ''Obviously, it's ill-timed because you have a lot of rain and snowfall in areas where people are trying to move around town or fly or drive out of town.''
More than 43 million people are expected to travel over the long holiday weekend, according to the AAA automobile organization. About 39 million of those will be on the roads, while more than 3 million people are expected to fly.