Interesting point made in this article:
http://www.freerepublic.com/focus/f-news/1058988/posts Breaches seen as terrorist tests
The arrest of a Sudanese passenger carrying bullets after a trans-Atlantic flight from Washington Dulles International Airport to London this week follows a series of breaches, and an airline security analyst suspects terrorists are testing the system.
"It would be a mistake to brush this off," said Charles Slepian of the Foreseeable Risk Analysis Center. "We should be more concerned with their ability to blow up a plane than to hijack one."
A leaked FBI memo reported last week by British news outlets, including the London Times, says suicide terrorists are plotting to hijack trans-Atlantic planes by smuggling "ready to build" bomb kits past airport security, and later assembling the explosives in aircraft bathrooms.
"Terrorist operatives are more confident that they can successfully smuggle [bomb] components, rather than fully assembled bombs past airport security," the FBI memo said.
Mr. Slepian said the combination of the FBI memo and several recent security incidents indicate that terrorists are probing airline security procedures. The recent breaches include:
(see link for list)