Like many people, I spend a lot of time in airport terminals, and I often think that they must be an awfully appealing target to terrorists. The largest airports have huge terminals teeming with thousands of passengers on any given day. They serve as conspicuous symbols of American consumerism, with McDonald’s restaurants, Starbucks coffee shops and Disney toy stores. While airport screeners do only a so-so job of checking for guns, knives and bombs at checkpoints, there’s no checking for weapons before checkpoints. So if the intention isn’t to carry out an attack once on board a plane, but instead to carry out an attack on the airport itself by killing people inside it, there’s nothing to stop a terrorist from doing so...
To prevent [attacks similar to the 2002 attack at the El Al ticket counter at LAX and the 2007 attempted car bombing at the Glasgow airport] — and larger ones that could be catastrophic — what if we moved the screening checkpoints from the interior of airports to the entrance? The sooner we screen passengers’ and visitors’ persons and baggage (both checked and carry-on) for guns, knives and explosives, the sooner we can detect those weapons and prevent them from being used to sow destruction.
The problem with this reasoning is that airport terminals aren't especially attractive targets for terrorists, incidents of terminal attacks notwithstanding. Airplanes are attractive targets, for a number of reasons. Airport terminals just form another class of places where large numbers of people congregate. They're no more attractive than shopping malls or sports stadiums or movie theaters. Why would you have onerous security for airport terminals but not the other places? Would the security actually deter or prevent any attacks, or would it simply make some people like Ervin feel better? As Schneier writes,
This is a silly argument, one that any regular reader of this newsletter should be able to counter. If you're worried about explosions on the ground, any place you put security checkpoints is arbitrary. The point of airport security is to prevent terrorism *on the airplanes*, because airplane terrorism is a more serious problem than conventional bombs blowing up in crowded buildings. (Four reasons. First, airlines are often national symbols. Second, airplanes often fly to dangerous countries. Third, for whatever reason, airplanes are a preferred terrorist target. And fourth, the particular failure mode of airplanes means that even a small bomb can kill everyone on board. That same bomb in an airport means that a few people die and many more get injured.) And most airport security measures aren't effective.