No major delays were reported as airlines began screening all baggage under the federal Aviation and Transportation Security Act.
Waiting to board an American Airlines flight from Dallas to New York, Sandra Latosky, 29, said she felt no safer because of the new law.
"It's kind of like a fake kind of thing," she said.
The law allows airlines to use one of four methods to better track baggage: explosive-detection machines, hand searches, bomb-sniffing dogs, or making sure checked luggage had a boarded passenger to match.
A CBS News poll finds 66 percent of Americans say screening all checked baggage will make flying safer. But most, 70 percent, say the screening will also cause serious delays. Overall, 44 percent of Americans say the airlines do an excellent or good job following government safety and security regulations; while a larger number, 49 percent, give the airlines a rating of fair or poor.
Critics, including some members of Congress, say the measures aren't enough to truly improve safety. Then there's George Lax, a New York City attorney who showed up 2½ hours early Friday for his flight to Miami.
"It's all hype," he said. "It's psychological to make people relax. The only way they're going to do it is to take every bag and X-ray it. And even then you can't be sure."
Not everyone was so disgruntled.
"We're here early enough and I think it's going very well," said Ken Miller, who was traveling from Denver to Florida. "It's very straightforward."
The couple's bags were opened and searched by hand. "We've had our bags opened before so it's nothing new," Miller said.
Airlines will be responsible for security until Feb. 17, when the federal government takes over. Under a congressional mandate, all baggage will have to be screened with explosives-detection machines by the end of the year.
Julia Bishop-Cross, a spokeswoman for American Airlines in St. Louis, said she wasn't surprised that travelers noticed little change Friday. She said American switched its operations several days ahead of the deadline.
"It's pretty transparent to our customers," she said. "So much of this is going on behind the scenes."
However, at Los Angeles International Airport, several people waited in line for 20 minutes just so someone could tell them what line to wait in.
"It's too confusing," said Melissa Johnson, 31, who was flying back to Minneapolis. "They didn't plan it very well. They needed a better system to tell people where to go."
Most airlines were expected to choose the bag-matching option, meant to prevent someone from checking a bag full of explosives without actually boarding the plane. Critics say that does little to discourage a suicide bomber.
Under the law, bags are only matched to passengeron the first leg of a trip, not connecting flights. While that's meant to prevent delays, Rep. Jim Oberstar of Minnesota, the top Democrat on the House Transportation Committee, said that amounts to "an Achilles' heel in the security system."
Matching bags with passengers also could prove troublesome if someone manages to check luggage and then misses the flight.
That scenario played out at least once Friday, when several bags were yanked from a plane at the airport in Manchester, N.H. But the incident caused no delay and airport Director Kevin Dillon said it proved the system works.
Air traffic at nearly all the nation's major hubs was flowing nicely by midday, from New York City's La Guardia and Kennedy airports to Chicago, Detroit, Baltimore, Miami, Denver, Minneapolis and Seattle, among others.
The carriers themselves also had no complaints; about 85 percent of Atlanta-based Delta Air Lines' flights worldwide were arriving on time.
"That's very, very fine for a midwinter day," spokesman John Kennedy said.
In Philadelphia, airport workers wheeled free food-and-drink carts to ease the anticipated wait, though the only grousing seemed to come from travelers shivering off the 30-degree chill at a curbside check-in.
"I don't mind this at all," said Phoenix-bound Jill Hannagan, 44, of Wilmington, Del. "I just wish I had my hat."
© MMII, CBS Worldwide Inc. All Rights Reserved. This material may not be published, broadcast, rewritten, or redistributed. The Associated Press contributed to this report