Potential terrorists need only read the newspapers to learn that current precautions may not be sufficient to prevent future acts of sabotage,. Nor need terrorists limit themselves to brief newspaper accounts: A surprising amount of detailed information is available on the web And, broadly viewed, the 1990's do not indicate any widespread disavowal of violence against innocent civilians. Terrorism grew in some parts of the First World unaccustomed to it: In the US, lethal bombings occurred at Oklahoma City and New Yorks World Trade Center; in Japan, poison gas was released in the Tokyo subway The decade also saw a horrific plan to attack civil aviation. In 1996, a defendant was convicted in New York of a(narrowly-averted) plot to destroy a dozen US jets coming home from Asia.(As part of the scheme, the conspirators successfully exploded a small bomb on a boeing 747 in the Philippines. One terrorism expert offered the less-than- reassuring view that the plot could have never felled twelve planes; at most, it would have claimed“ four or five.” That Table 2 may offer a fragile basis for comfort was suggested in October 2000 when terrorists deployed a powerful bomb in Yemen against the USS Cole. A day later, a dispatch from London'reported that"fear of terrorist attacks after the explosion of violence in the Middle East hammered global airline shares Friday. "One analyst stated that At the moment, aeroplanes are not the number-one target. But they could be Another opined that" it is a relatively easy jump (from recent events to imagine someone also doing something to aircraft. What might make airlines tempting targets is that an attack on an airplane has a realistic chance of killing everyone aboard. That prospect stands in contrast to outcomes in the Tokyo subway and the World Trade Center, where the aim may have been to kill hundreds if not thousands of people, but the actual death tolls were, respectively, twelve and six Runway collisions There were two runway collisions in the 1990s, which killed a total of 30 First-World jet travelers. Both events occurred in the US; Table 3 presents mortality risk statistics based atter Table 3 goes here However, the years ahead could well be more dangerous, for the simple reason that airport traffic is growing. Indeed, intuition suggests that runway collision risk could6 Potential terrorists need only read the newspapers to learn that current precautions may not be sufficient to prevent future acts of sabotage4,5,6. Nor need terrorists limit themselves to brief newspaper accounts: A surprising amount of detailed information is available on the web. And, broadly viewed, the 1990’s do not indicate any widespread disavowal of violence against innocent civilians. Terrorism grew in some parts of the First World unaccustomed to it: In the US, lethal bombings occurred at Oklahoma City and New York’s World Trade Center; in Japan, poison gas was released in the Tokyo subway. The decade also saw a horrific plan to attack civil aviation. In 1996, a defendant was convicted in New York of a (narrowly-averted) plot to destroy a dozen US jets coming home from Asia. (As part of the scheme, the conspirators successfully exploded a small bomb on a Boeing 747 in the Philippines.) One terrorism expert offered the less-than￾reassuring view that the plot could have never felled twelve planes; at most, it would have claimed “four or five.” That Table 2 may offer a fragile basis for comfort was suggested in October 2000, when terrorists deployed a powerful bomb in Yemen against the USS Cole. A day later, a dispatch from London7 reported that “fear of terrorist attacks after the explosion of violence in the Middle East hammered global airline shares Friday.” One analyst stated that “At the moment, aeroplanes are not the number-one target. But they could be.” Another opined that “it is a relatively easy jump (from recent events) to imagine someone also doing something to aircraft.” What might make airlines tempting targets is that an attack on an airplane has a realistic chance of killing everyone aboard. That prospect stands in contrast to outcomes in the Tokyo subway and the World Trade Center, where the aim may have been to kill hundreds if not thousands of people, but the actual death tolls were, respectively, twelve and six. Runway Collisions There were two runway collisions in the 1990’s, which killed a total of 30 First-World jet travelers. Both events occurred in the US; Table 3 presents mortality risk statistics based on the pattern. Table 3 goes here However, the years ahead could well be more dangerous, for the simple reason that airport traffic is growing. Indeed, intuition suggests that runway collision risk could