Airline security has already been perfected in Israel, where highly trained screeners have been routinely detecting and preventing terrorists from boarding aircraft for decades. In the United States, however, technology will likely substitute for our lack of qualified screeners.

Following are methods used to detect terrorists:

Eye Contact

In order to board an El Al aircraft in Tel Aviv, a terrorist has to get past multiple levels of highly trained screeners, each of whom looks the passenger straight in the eye and asks pointed, personal questions. Any nervous twitch, diversion from eye contact or other slight body-language telltales will result in the passenger having to wade through several more intensely confronting screening sessions—from meticulously going through every item in your carry-on bag to a complete strip search.

A shortage of highly trained security screeners in the United States, however, makes technology the answer to securing airports here. You already know about the millimeter wavelength full body scanners that the U.S. airports are starting to employ, but below are a few other alternatives that you may not have heard about.

WeCU

WeCU Technologies (Caesarea, Israel) automates the security procedures that Israeli screeners use by substituting symbols on a video screen for the pointed questions and video recognition software algorithms for eye contact. As passengers approach the security checkpoint, they are presented with images that terrorists cannot help but recognize, such as terror-group logos and symbols commonly used on extremist Websites. Video cameras and noninvasive sensors then scan viewers as they walk past the images, looking for signs of involuntary recognition, such as pupil dilation or a rise in skin temperature.

Gate Keeper

With its Gate Keeper, Nemesysco (Natania, Israel) automates the pointed question-and-answer session that Israeli screeners use. Passengers waiting in line for security screening would verbally answer a short questionnaire. Voice recognition software then analyzes parameters in the passengers' responses for suspect mental states like dishonesty. Nemesysco claims its voice analysis algorithms can identify the emotional state of the passenger and distinguish between criminal intent and the typical exhausted or excited passenger.

FAST

The Department of Homeland Security has its own automated lie-detector technology called the Future Attribute Screening Technology that it is currently testing. Like Gate Keeper, FAST is intended to identify hostile intent in a passenger by asking questions. But instead of voice analysis, FAST observes pulse rate, skin temperature, breathing, facial expression, body movement, pupil dilation and other cues.

Puffers

U.S. airports may soon be asking all passengers to walk through "puffers" that can detect trace amounts of explosives. GE Security's EntryScan, for instance, is a walk-through portal that puffs air onto the traveler to draw out vapors from underneath clothing, then analyses them for explosive residue. A handheld version called the VaporTracer has a stalk that could be inserted into sensitive areas that screeners in the United States are not allowed to touch.