Let's switch settings for a moment, from airport to train station. Two months ago I was visiting Spain, and I spent some time on the Madrid subway. I also passed through Atocha Station, the city's commuter rail hub that suffered the bulk of the death toll during the March 2004 bombings that killed 191 people and injured almost 2,000 others. Walking through the passageways and corridors of Atocha, there are few reminders of the carnage. Security is noticeable, but unobtrusive. There's a simple and discreet memorial to the bombing victims. The U.K. Guardian describes it better than I can:

"The Atocha memorial lacks any hint of artistic grandeur. Yet its very banality is also somehow appropriate -- for this war will be won or lost not in some grand showdown but in a trillion tiny everyday encounters, like those of commuters pouring off a suburban train."

On the subway platforms and in the cars, there were no checkpoints, no metal detectors, no ominous security placards. To the best of my limited ability to understand Spanish, I heard no public address announcements urging people to look for suspicious packages or report unusual activity.

Here in Boston, on the other hand, a person can't travel two stops on the local subway without hearing the recorded voice of Gov. Mitt Romney imploring riders to watch for unattended packages and drop a dime on anyone who acts strangely. It's all part of a U.S. Department of Transportation campaign called Transit Watch, with the accompanying slogan, "See something? Say something." For those uncertain what a terrorist might look like, the MBTA has been handing out Transit Watch pamphlets that carefully outline the modus operandi of the typical evildoer. It advises passengers to watch for individuals who show visible signs of nervousness, including "excessive perspiration." (Come July, that ought to get just about everyone in Park Street station shuttled off to a barracks at Guantánamo Bay.) The front of the Transit Watch booklet, in a gesture so shamelessly Orwellian that at first glance I thought it was a parody pamphlet, features a logo with a little eye staring out at you -- like the one on the back of a dollar bill, except creepier and all too explicable.

All in the name of prevention, we're told. When I detailed my experience in Madrid to a friend, he snapped, "Yeah, we'll see how they react when they get hit again."

Except the Spanish, as victims, are sensible enough to realize that there's only so much you can do, and don't squander their resources on measures that do nothing to prevent bombings and everything to waste time and infringe on people's rights. The citizens of Madrid might be fearful of additional carnage, but they're also sensible and, in a quiet way, defiant. Our own reaction to terrorism has been anything but defiant -- other than dropping bombs and shooting rockets at people, most of whom have nothing to do with the problem.

Already New York's Metropolitan Transportation Authority, overseer of Gotham's buses and subways, has implemented random bag searches, and the TSA has begun dispatching armed "viper" teams to canvass the nation's railroads and public transit systems. I shudder to envision our reaction should a terrorist -- or a reactionary thug like Timothy McVeigh -- strike an American subway. New York, Boston, Philadelphia or Chicago would be brought to a grinding halt -- at least until the X-ray machines and soldiers were in place at every station.

In closing, for those whose diet doesn't include enough fear and skewed thinking, I recommend the new book by our old friend Annie Jacobsen. She has turned her 2004 online serial, which began after she shared a Northwest Airlines flight to California with a group of rambunctious Syrian musicians, into "Terror in the Skies -- Why 9/11 Could Happen Again," published by the Spence Publishing Company (Amazon sales rank: 100,448). If you're new to this story or would like a recap, click here and begin working backward.

I bring this up at my own peril. Two summers ago, after my five-part teardown of Jacobsen's articles, several Ask the Pilot regulars wrote to warn me that if I so much as mentioned her name one more time, they would never again read a word of mine. But considering her story's remarkable level of traction, and apropos of recent security news, I think it's worth mentioning -- with apologies.

To the best of my knowledge, books aren't normally released on Sundays, but in a perversely commemorative spirit, Spence made sure "Terror" hit the shelves exactly on Sept. 11, 2005. Since then, it has received some positive spin in places you might expect. "Terrorists might not have given up on planes," begins a review by Anne Morse, writing for National Review.

I couldn't agree more, albeit with totally different ideas of how, exactly, they might go about their business.

The central problem with Jacobsen's suppositions today are the same as they were in 2004: Why would gangs of foreign operatives, on practice missions, go around brazenly risking exposure in the middle of the most intensive anti-terror blitz in history? She asks us to assume that 12 men were deployed on Northwest Airlines flight 327, and that similar occurrences, routinely witnessed by passengers and crews, have been widespread all over the country -- and overseas as well. Personally, I've never spoken to an airline pilot who vouches for this conspiracy.

By meager extrapolation, there would have to be dozens, or possibly hundreds, of operatives, flying around the nation conducting not-so-covert operations. None of whom have ever been caught. The government, Jacobsen maintains, is complicit by refusing to acknowledge these so-called dry runs, and/or turning a blind eye.

Why does that strike me as so much paranoid fantasy?

And should we really be surprised? "The terrorists" are playing the role of latest invisible scare, just as the communists did before them -- a rallying cry for those who traffic in fear. Sadly, widespread delusions of unseen, anti-state conspirators in our midst are nothing new in human history. When I interviewed her, Jacobsen went to lengths to assert that she is not a right-wing crackpot, or even a conservative. At last check on Amazon, Jacobsen's "Terror" is paired with a title by Paul Sperry called "Infiltration: How Muslim Spies and Subversives Have Penetrated Washington." Gary Boettcher, president of the Coalition of Airline Pilots Associations, has penned one of "Terror's" two editorial reviews (both are but a single sentence long).

Says Boettcher, "The terrorists are probing us all the time." For what it's worth, I never heard of the Coalition of Airline Pilots Association until reading about Annie's book.

And as for obvious self-promotion, two can play at that game. If you're looking for a stocking-stuffer from Amazon, I suggest this one.

Next time: Nothing about security. A look at the Southwest Airlines incident in Chicago; another crash in Nigeria; and what happens when a plane gets hit by lightning?

- - - - - - - - - - - -

Do you have questions for Salon's aviation expert? Send them to AskThePilot and look for answers in a future column.

Recent Stories