I am not sure what is more disturbing: the ease with which irrational passengers can get other people thrown off flights or the dismal state of math in the United States that calculations are now unrecognizable to many passengers. University of Pennsylvania economics professor Guido Menzio, an award winning mathematician, was asked to leave a flight from Philadelphia to Syracuse because a woman sitting next to him panicked at the sight of his scribbling some strange code on papers. It turns out Menzio was trying to solve a differential equation. Ironically, the very fact that he was using a plus sign in his equations showed that he was not an Islamic extremist.
Menzio was on his way to Ontario, Canada and was engrossed in the equation. The woman next to him said that she was concerned that he was not talkative and gave a note to the flight attendant that she was not feeling well. She later told the flight attendant that she was fearful of Menzio who was then escorted off the flight.
Menzio was clueless about the reason and thought that they were asking about the woman, who he described as a bit odd. Then it became clear that they were really interested in him. Menzio showed the police that this is called mathematics.
The 41-minute flight took off more than two hours after its scheduled departure. The woman apparently did not rejoin the flight.
It is not clear why at least one person could not easily recognize math and the obvious fact that this was a ridiculous overreaction.
Of course, mathematician E.T. Bell once warned “Obvious is the most dangerous word in mathematics.”