Steph Solis

USA TODAY

A math equation landed an Ivy League professor on an American Airlines flight in questioning Thursday under suspicion of being a terrorist.

Guido Menzio, an economist at the University of Pennsylvania, was working on a differential equation while waiting for the Syracuse-bound plane to take off from Philadelphia, the Washington Post reported. He had to present the findings of a working paper at Queen's University. But a passenger somehow mistook the equation for Arabic or some sort of Islamic code for a terrorist attack.

That's how the 41-minute flight ended up delayed by two hours—a false alarm the olive-skinned, curly, dark-haired native Italian chalked up to racial profiling.

Per the Post:

And then the big reveal: The woman wasn’t really sick at all! Instead this quick-thinking traveler had Seen Something, and so she had Said Something. That Something she’d seen had been her seatmate’s cryptic notes, scrawled in a script she didn’t recognize. Maybe it was code, or some foreign lettering, possibly the details of a plot to destroy the dozens of innocent lives aboard American Airlines Flight 3950. She may have felt it her duty to alert the authorities just to be safe. The curly-haired man was, the agent informed him politely, suspected of terrorism. The curly-haired man laughed. He laughed because those scribbles weren’t Arabic, or another foreign language, or even some special secret terrorist code. They were math.

Menzio said there were other factors that may have led to a misunderstanding. The blond-haired 30-something woman asked if Syracuse was home for him, and he answered curtly. He avoided other questions. He seemed, according to the Post, "perhaps too laser-focused" on his notepad.

That's when she slipped a note to the flight attendant and the plane returned to the gate.

American Airlines confirmed that the woman expressed suspicions about University of Pennsylvania economics professor. She said she was too ill to take the Air Wisconsin-operated flight.

"I thought they were trying to get clues about her illness," he said in an email. "Instead, they tell me that the woman was concerned that I was a terrorist because I was writing strange things on a pad of paper."

Menzio said was treated respectfully, but he expressed concerns about the lack of communication: "Not seeking additional information after reports of 'suspicious activity' ... is going to create a lot of problems, especially as xenophobic attitudes may be emerging," he said.

Contributing: Associated Press.