DETROIT (WWJ) – There’s word that al-Qaida’s affiliate in Yemen tried to destroy a U.S.- bound jetliner with a bomb around last week’s anniversary of the killing of Osama bin Laden.

The CIA thwarted the plot, which was to have been carried out using a bomb with a new type of design, believed to be an upgrade of the underwear bomb that failed over Detroit on Christmas of 2009.

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Richard Chasdi, author of two books on terrorism and adjunct assistant professor at Wayne State University, wonders why al-Qaida is fixated on attacking airliners.

“That’s the common wisdom, is that they are still interested in aircraft assaults and it remains unclear to me why the complete fascination with that,” said Chasdi.

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“Attacking aircraft is a high symbolic value and at the same time is a very difficult to do, especially in todays age,” said Chasdi.

“More pedestrian targets, such as malls, everyday venues people travel to and visit are of concern because by their very nature they are much harder to protect against,” he said.

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Chasdi believes this most recent attempt shows that if there are existing security provisions in place, terrorists will work diligently to overcome them.