Anne Applebaum ["Airport Security's Grand Illusion," op-ed, June 15] is on the money when she takes the Transportation Security Administration's screening function to task by comparing costs to benefits. The TSA has shown little understanding that the greatest security vulnerability exists at the backside of an airport, where delivery trucks, catering vehicles, vendors of all stripes and escorted vehicles have access to secured areas with a mere flash of an approved airport ID.

At the TSA's inception, Federal Aviation Administration special agents, who ensured that airports secured their perimeters, were almost all deployed to be screening supervisors and air marshals. This not only reduced security where it was needed most but also brought no appreciable improvement in passenger screening.

Nearly all smuggling -- be it of drugs, illegal immigrants or security-related items -- occurs in cargo or at the back gates of airports, yet this problem goes unaddressed in any meaningful way. This is where a cost-benefit analysis should be focused.

BRIAN REED

Arlington

The writer is an aviation security consultant.

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Recently my mother, husband and I flew to Manchester, N.H., from Philadelphia. My mother had left all of her identification at home, so she had to undergo a more thorough security check than someone with ID.

In Philadelphia, a screener ran a wand over her and moved jewelry and eyeglasses out of the way when they caused the wand to beep. My mother didn't have to remove her shoes, and although a screener ran her hand around the outer edge of my mother's purse, she didn't remove anything from it.

In Manchester, every time something caused the wand to beep, it had to be removed and put through the X-ray machine (eyeglasses, jewelry, etc.). Everything in my mother's purse was taken out, and she had to remove her shoes.

While I don't begrudge the extra checking, because my mother didn't have ID with her, I found it interesting that what was acceptable at one airport wasn't acceptable at another. Seems like we're spending an awful lot of money on the Transportation Security Administration to have different standards at different airports.

SUE BOLTON

Mohnton, Pa.

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I agree with Anne Applebaum that U.S. airports would get more bang for the buck by investing in an Israeli-style passenger questioning system. Scrutiny of baggage and travel documents at multiple checkpoints, no matter how rigorous, is no substitute for scrutiny of the passenger.

When I visited Israel in winter 2004, I was questioned three times by El Al security personnel. Each time, the person studied my face and manner, not just my papers. By the time the third person asked me the same questions (Why was I going to Israel? Why now? Who was I going to stay with? Where did that person live and work? Who else did I know in Israel? etc.) in the same low-key and matter-of-fact -- but relentless -- manner, I was quite unnerved. And I had nothing to hide.

When I finally got on the plane, I felt shaken -- but also a heck of a lot safer than if El Al had merely X-rayed my shoes.

LISA GREGORY

Washington