An Airport Security Secret

(CBS)  Since Sept. 11, security at America's 400 airports has been ratcheted up in a very public way: more bomb sniffing dogs, explosive scanners and armed patrols.

But, there's a secret more invasive side to security the government doesn't want you to see.

"The truth is the best measures in terms of airport security are the measures of which travelers will never see and of which they will never know anything about," said Darryl Jenkins of George Washington University.

It's a computer-based profiling system aimed at identifying passengers who may present a threat.

For years, airline ticket agents have quietly looked for red flags: passengers paying cash or buying one way tickets, people traveling alone, or those checking no bags have been targeted for closer scrutiny.

But, reports CBS News Correspondent Bob Orr, sources say federal authorities are developing a vastly expanded profiling system - linking government and private databases - to allow airlines to probe even more deeply into passengers' lives.

Credit card and spending histories, travel habits, phone records, criminal backgrounds and living arrangements may all be used to rank passengers by risk. Even census data -- those from high-crime neighborhoods may face extra screening.

Civil liberties advocates assail expanded profiling as a huge invasion of privacy. But, aviation authorities say it's the best way to "clear" the 99 percent of travelers who pose no threat so that security can zero in on those who might.

One alternative is a voluntary system in which a passenger would surrender personal information and undergo a criminal background check in exchange for a "Safe Traveler Card" that would expedite the trip through airport security.

The card containing images of a passenger's fingerprints or eyes would be useless to a thief and virtually impossible to counterfeit.

"It's logical that you'd want to set up a system that way so that you and I get through the system very quickly and somebody who may have ties to the al Qaeda network gets looked at a little more closely than they are now," said Richard Norton of International Biometric Association.

It could take years before smart cards and expanded profiling are completely on guard at U.S. airports. But, air travel has already changed as has the way the government and the airlines look at passengers.