A MARTINEZ, HOST:
Twenty years ago, you could arrive at an airport at the last minute and walk through a metal detector without taking off your shoes. But that has changed since the September 11 terrorist attacks as airport security evolved to meet new threats.
NPR's David Schaper is in Chicago with more.
DAVID SCHAPER, BYLINE: The 9/11 hijackers strolled through airport security checkpoints with relative ease. A few were flagged by a passenger prescreening system. But that only meant that their checked bags were held off the planes until they boarded. And if they set off metal detectors, well, knives and razor blades were allowed back then.
JEFF PRICE: It was so easy. A lot of us were surprised it hadn't happened sooner.
SCHAPER: Jeff Price is an aviation security expert at Metropolitan State University in Denver and was assistant security director at Denver International Airport at the time.
PRICE: Before 9/11, security was almost invisible. And it was really designed to be that way.
SCHAPER: Airport security was done by private contractors usually hired by the airline. So it was often the lowest bidder, with little federal oversight. It had been so long since any terrorist incident involving commercial airliners in the U.S. that Price says the security industry had grown complacent.
PRICE: 9/11 was really a gigantic reset switch for aviation security.
SCHAPER: Immediately after, heavily armed National Guard troops patrolled airports. And knives mace and a lot of other potentially dangerous items were banned. In November of 2001, President Bush signed the Aviation and Transportation Security Act, creating the TSA. The law also required all checked baggage to be screened, cockpit doors to be reinforced, and it greatly expanded the Federal Air Marshal Service.
Over the years, new threats led to additional security protocols. A failed attempt to detonate a shoe bomb is why we must take off our shoes. A foiled plot to mix explosive chemicals hidden in soft drink bottles led to the 3.4 ounce limit for liquids and gels. And one terrorist attempt to ignite explosive materials smuggled in his underwear led to highly detailed body image scanners.
So how is it all working? To those who were on the front lines of security at Chicago's O'Hare Airport, the technological advances are dramatic.
DEB SCOVEL: In the old saying, it's come a long way baby.
SCHAPER: Checkpoint supervisor Deb Scovel had been with the TSA almost since the beginning - 19 years.
SCOVEL: When I first started here, we did everything by hand. The only actually machinery machinery we had besides a very old, old X-ray was the walk-through metal detectors. Everything else, you did by hand. If you had to check a bag, you were in it.
SCHAPER: Now computed tomography machines examine baggage in detail that rivals medical-grade CT scans.
SCOVEL: It's very detailed. It's very detailed. I can tell you the difference between Irish Spring and Dove soap. Yes, I can (laughter).
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SCOVEL: You can almost tell the difference between an Apple and a Dell laptop. They're very detailed...
UNIDENTIFIED PERSON: On the belt.
SCOVEL: ...Very detailed.
SCHAPER: And, Scovel says, the new advanced image body scanners that we stand in with our feet apart and arms in the air can detect the smallest of items.
SCOVEL: This thing, I think, picks up pocket lint. I swear it does. This will pick up anything that's not normal to a body contour.
SCHAPER: But unlike previous high-resolution scanners that raise privacy concerns, these show only an avatar with suspicious areas highlighted. There's new credential authentication technology that scans IDs and passports, behavior detection officers to look for suspicious behavior, and more canine units sniff for explosives. The TSA's known traveler programs, like PreCheck, help it better focus on higher-risk and unknown travelers. And the agency has begun voluntary facial recognition and biometric screening at some airports. This all comes at a hefty price. The TSA budget last fiscal year was nearly $8 billion. Passengers pay a September 11 security fee of $5.60 each way. The TSA's deputy security director at O'Hare, Lou Traverzo, says the multiple layers of security work. But will they prevent another 9/11 kind of attack?
LOU TRAVERZO: I would never say never. Are we safer? Absolutely. But people are very creative. The threat's very creative. And it's up to us to anticipate that.
SCHAPER: Aviation security expert Jeff Price agrees. But he says the key is being nimble.
SCHAPER: Our threats have continued to change. And our regulations and our lawmaking is not always fast enough to adapt to those changes
SCHAPER: And Price and other experts caution that even though there hasn't been a successful attack against commercial aviation in this country since 9/11, there needs to be continued vigilance.
David Schaper, NPR News, Chicago.
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