Special thanks to Paul Hurd of PerkinElmer Detection Systems for his assistance with this article.
Millions of people fly every day. The vast majority of them are law-abiding folks who have no intention of harming anyone. But there is always the possibility that a terrorist or a criminal is hidden among the masses. Also, many people with no intent to cause harm may accidentally carry a hazardous material onto the plane. To avoid these problems, airport security is an important part of any airport.

Photo courtesy Photo courtesy Federal Aviation Administration (FAA)
Millions of people fly on thousands of planes every day.

Imagine a terrorist trying to blow up or hijack a plane. What are all of the different techniques that the terrorist might use to get a bomb into position? A terrorist could:

  • plant a bomb in an unsuspecting passenger's luggage.
  • smuggle a bomb in his luggage
  • strap a bomb or gun onto his body
  • walk onto the tarmak by hopping a fence and approach a plane from the ground
Airport security tries to cut off all of these different routes. In this edition of HowStuffWorks, you'll learn about the metal detectors and X-ray systems used by airport-security personnel. You will also find out what you definitely can't carry on a plane.