A flight from Philadelphia to Syracuse usually takes about 41 minutes. Unless there is a two hour delay because one passenger thinks that another passenger doing a math problem next to them is a terrorist.
American Airlines confirmed a passenger on a flight last Thursday was sitting next to a man who was scribbling on a notepad, and expressed concerns that he might be a terrorist. That man was University of Pennsylvania professor and award-winning economist Guido Menzio. He was working on a differential equation (remember those? Me neither), but Menzio said he was told the woman who was sitting next to him thought he might be a terrorist because of his complex notes.
The woman initially told the flight crew she was too ill to take the flight, but when she deplaned to take another flight she disclosed she was actually just feeling ill about Menzio possibly being a terrorist.
The threat was deemed "not credible," at least in a terrorism capacity. A differential equation, especially at the level Menzio was presumably operating, is still very much a threat to me. But certainly not worthy of raising terrorism concerns and delaying a whole flight. More like, "this guy sitting next to me is so much smarter than I am and probably won't want to help me find the hidden items in the back of my Highlights magazine" kind of threatening.
Menzio told local media he was troubled by the woman's ignorance as well as "a security protocol that is too rigid, in the sense that once the whistle is blown everything stops without checks, and relies on the input of people who may be completely clueless."