Regardless, a small number of airports actually utilize full body scanners and their effectiveness in deterring terrorists is questionable. Related to this is the notion that airport security measures typically follow what previous terrorists have attempted. For instance, somebody sneaks on to an airplane with liquid explosives in their shoes and many airports begin checking shoes. By that time the damage is done and the next plot is different. Airport security is not progressive. Second, as stated above the real progress in detecting terrorist plots has come from intelligence work and not from airport screening. Finally, the number of terrorist attacks foiled since 9/11 and the number of deaths due to terrorism outside of war zones indicates that an American citizen is more likely to die from heart disease or cancer than from a terrorist attack. This is not to say that airport security should be lax; however, airport security could be effective with very simple measures such as the ones used in Europe. There is no need to spend millions or billions of dollars on full body scanners, increased TSA agents, etc.