FILE -This Dec. 25, 2009 file photo shows Northwest Airlines Flight 253 on the runway after arriving at Detroit Metropolitan Airport from Amsterdam. Officials say a passenger aboard the plane was trying to ignite an explosive device Friday. (AP Photo/J.P. Karas, File)AP – A man who claimed to be an agent of al-Qaida was charged Saturday with trying to blow up a Northwest Airlines flight on Christmas Day as it was preparing to land in Detroit, officials said.