BISMARCK, N.D. — A planned boycott of airport security scanners was a bust, but holiday travelers in the western U.S. had to contend with a chaotic mix of snow, sleet and ice.

A powerful storm system closed roads and delayed flights from Anchorage to Salt Lake City, and promised messy weather Thanksgiving Day in the Dakotas. Freezing rain glazed roads across the Midwest.

But the cascading delays and lines that many feared would result at airports from the so-called National Opt-Out Day didn't materialize Wednesday, among the busiest travel days of the year.

The loosely organized Internet campaign encouraged travelers to protest new security screening by opting for time-consuming pat-downs.

Few passengers seemed to participate. Lines moved smoothly, and there was no more or less congestion at major airports than in previous years.