The effects of a thwarted terror attack were evident at Kennedy Airport Saturday, as travelers said they were alarmed that someone in a post-9/11 world could manage to sneak aboard an explosive device.

"Security's definitely not good enough," said Hekim Karabulut, a 33-year-old carpet salesman from San Francisco.

"If it was something stronger," he said, "it could have blown a window - many people would lose their life."

Andrey Nesenchuk, a 22-year-old car dealer from Rochester who was spending the Christmas weekend sleeping in airports because of flight delays before catching a plane to Eastern Europe, was befuddled.

"I don't feel safe," Nesenchuk said. "Everything's so shaky."

Jennifer Frank and Kevin Cooper, arriving at Kennedy on Virgin America from Los Angeles had opposite views on airport security that allowed the Nigerian suspect, Umar Farouk Abdulmutallab, to attempt to explode the device on the Amsterdam-Detroit flight.

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"On a large scale, I do not think it is possible to stop everyone, every time, 24/7," said Frank, 26, an accountant. "There will always be somebody who can get by with something."

But Cooper, 21, her boyfriend, said there was no excuse.

"That's not security," he said. "How do you not notice something [like an explosive device] in someone's pants?"

Passengers also noticed that some airlines were starting new security procedures.

Maxine Hawthorne, a 45-year-old restaurant owner from England, said her Delta Air Lines flight was about 90 minutes from landing at JFK when she noticed unusual behavior by the crew.

"We were all told to stay in our seats . . . [The captain] just said it was new procedure . . . I wondered why these new procedures? I thought something was wrong."

For others, Saturday was business as usual.

Lee and Debbie Ellison, both 51, of Richmond, Va., who were on standby for a flight to Dubai, said they feel safe and that security is adequate.

"I think the danger of getting hurt on an airplane is just so super small," said Lee Ellison. "It's smaller than if you're driving."

Natasha Antonucci, a 27-year-old from Manhattan who was at Kennedy to fly to Jamaica with her brother, Kyle, said she "didn't think twice" about boarding a plane - despite what happened aboard Flight 253.

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"Flying with him," she said, gesturing at her strapping, 22-year-old travel companion from Upper Saddle River, N.J. "I'm not worried."

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