Planes That Fly Over US Pose Security Threat: Expert Flights passing over, not landing in nation could house 'dirty bomb' By Mark Russell, Newser Staff Posted Dec 27, 2010 3:07 AM CST Updated Dec 27, 2010 7:00 AM CST 6 comments Comments Security experts argue that planes that fly over the United States but do not land there pose a security risk. (?CraigMoulding) (Newser) – The thousands of cargo and passenger flights that fly over but don't land in the US each week aren't subject to full security screenings—and pose a potentially deadly risk to Americans, reports the Washington Post. The cargo aboard these flights isn't screened to federal standards, and passenger names aren't matched to the TSA's terror watch list. A terrorist could "explode a plane with a dirty bomb or a biological weapon or an actual nuclear weapon on board, and that material will spread wherever it crashes," said a counter-terrorism expert. Other countries "have their own cargo security protocols that apply to those aircraft," said a TSA statement, and scanning all flights carrying millions of packages a day is "totally unrealistic," said one transportation expert. Most overflight passenger planes are going to or from Canada, and 92% of the cargo planes are heading to or from Germany, according to FAA officials, who deny the flights pose a major security threat. As many as 3,000 flights cross over the continental US each week, but few of those pass over large population centers, said a spokesman for the International Air Transport Association. "It's a myth to say these overflights are the Wild West," said the spokesman.