1.   As horrific as using hijacked airliners is, the fact that terrorists are now using biological weapons is even more worrisome.

2.   No one ever imagined suicidal terrorist squads armed with box cutters using hijacked airliners as guided missiles.

3.   The United States decided to move them to an air base on Guam, using airliners chartered by a private relief group, the International Organization for Migration.

4.   But what happens when terrorists use commercial airliners as such weapons, killing thousands of civilians?

5.   Even so, U.S. intelligence officials were well aware that terrorists inspired by bin Laden had considered using airliners as weapons in the past.

6.   Intelligence officials were well aware that terrorists inspired by bin Laden had considered using airliners as weapons in the past.

7.   It contained no mention of using hijacked airliners as missiles, or of a specific date or location of attack.

8.   Terrorist attacks using commercial airliners as weapons represented a new threat that requires new methods of defense, the head of the U.N. agency overseeing civil aviation said Tuesday.