The Transportation Security Administration said very few passengers opted out. And there were only scattered protesters - including, presumably, a man seen walking around the Salt Lake City airport in a skimpy, Speedo-style bathing suit, and a woman wearing a bikini in Los Angeles.
After days of tough talk on the Internet and warnings of possible delays, some passengers decided to go to the airport especially early and were pleasantly surprised.
Retirees Bill and Margaret Selfridge arrived three hours ahead of schedule at the Minneapolis-St. Paul airport for their flight to Washington. It took only 10 minutes to get through the checkpoint at 8 a.m.
"Now we get to drink a lot of coffee," Bill Selfridge said.
Catherine Pfeiffer, 40, of Austin, Texas, changed planes at the Atlanta airport and said she had no major objection to the security screenings: "If you don't want to go through the hassle, don't fly."
A loosely organized effort dubbed National Opt-Out Day planned to use fliers, T-shirts and, in one case, a Scottish kilt to protest what some call unnecessarily intrusive X-ray scans and pat-downs. The security screenings have been lampooned on "Saturday Night Live" and mocked on T-shirts, bumper stickers and underwear emblazoned "Don't Touch My Junk," from a line uttered by a defiant traveler in San Diego.
But the weather was shaping up as a much bigger threat, especially in the West: A ferocious, early-season snowstorm pummeled the Rockies, bringing whiteout conditions to parts of the region and closing roads. It was expected to delay air travelers and people who probably thought they were doing the smart thing by driving. Also, heavy rain was forecast in the Midwest. And windy weather in New England could create snags.
More than 40 million people plan to travel over the Thanksgiving holiday, according to AAA, with more than 1.6 million flying - a 3.5 percent increase from last year.
Two protesters at the Phoenix airport held signs decrying "porno-scans" and drew sidelong glances from some passengers but words of support from others, who told them, "Thank you for being here."
The protesters, husband and wife Patricia Stone and John Richards of Chandler, Ariz., said the TSA has taken security too far.
"Just because you buy a plane ticket doesn't mean you have to subject yourself to awful security measures. It's not a waiver of your rights," said Stone, 44. "The TSA is security theater. They're not protecting us."
But at security lines at the airport, one of the nation's 10 busiest, lines were moving quickly and steadily. In fact, wait times for security checks at major U.S. airports from San Francisco to New York were 20 minutes or less Wednesday morning, according to the TSA, and no serious disruptions were reported
Asked early Wednesday if the protests were having any noticeable effect, TSA chief John Pistole told The Associated Press, "Not that we've seen overall. I mean we've, you know, had a couple of one-offs here and there."
"So far, so good," he said. "No long wait times or anything."
Earlier Wednesday, Pistole told ABC's "Good Morning America" that his agency is fully staffed to deal with problems and that travelers should be prepared for delays because of the threatened protests. For days, he has pleaded with Thanksgiving travelers not to boycott the body scans and delay other people.
"I just feel bad for the traveling public that's just trying to get home for the holidays," Pistole said, noting that TSA screeners "just want to get you through."
At least some passengers brushed aside claims the screenings were needlessly intrusive and too cumbersome.
Greg and Marti Hancock of Phoenix, on their way to a vacation in California, breezed through security after going through the body scanner.
"It was a day at the beach, a box of chocolates," said Greg Hancock, 61, who was chosen for the scanner after a golf ball marker set off the metal detector.
Marti Hancock, 58, said ever since she was in the air on Sept. 11, 2001, and thought there was a bomb on her plane, she has been fully supportive of stringent security: "If that's what you have to do to keep us safe, that's what you have to do."
At the Atlanta airport, 22-year-old Ashley Humphries was given a pat-down search of her chest and crotch by a female screener after bobby pins in her hair set off a metal detector.
"I can see how it would make someone uncomfortable, but I'm not easily offended, so it really didn't bother me as much," said Humphries, who was traveling with her fiance to spend Thanksgiving with family in Tennessee.
At Denver International Airport, Chris Maj, a 31-year-old computer programmer, carried a sign that read, "END THE TSA ASK ME HOW." He and three others handed pocket-size copies of the U.S. Constitution.
"They're touching breasts, they're touching buttocks, all of these places that if you or I were to touch, we'd go to jail," he said.
Another traveler, Robert Shofkom wasn't too worried about delayed flights, maybe just strong breezes. The 43-year-old from Georgetown, Texas, said he planned for weeks to wear a traditional kilt - sans skivvies - to display his outrage over body scanners and aggressive pat-downs while catching his Wednesday flight out of Austin.
"If you give them an inch, they won't just take in inch. Pretty soon you're getting scanned to get into a football game," the information technology specialist said.
Shofkom was disheartened when his wife informed him Tuesday that the Austin airport doesn't yet have body scans. But he decided to wear the kilt anyway.
One Internet-based protest group called We Won't Fly said hundreds of activists would go to 27 U.S. airports Wednesday to pass out fliers decrying the scans and the pat-downs.
"If 99 percent of people normally agree to go through scanners, we hope that falls to 95 percent," said one organizer, George Donnelly. "That would make it a success."
If enough people opt for a pat-down rather than a body scan, security-line delays could quickly cascade. Full-body scans for passengers chosen at random take as little as 10 seconds. The new pat-downs, in which a security agent touches a traveler's crotch and chest, can take four minutes or longer.
The full-body scanners show a person's contours on a computer in a private room removed from security checkpoints. But critics say they amount to virtual strip searches. Some have complained that the new enhanced pat-downs are humiliating and intrusive, too.
TSA officials say the procedures are necessary to ward off terror attacks like the attempted bombing of a Detroit-bound plane last Christmas, allegedly by a Nigerian man who stashed explosives in his underwear.