New York: An Italian economist said his flight was delayed for over two hours after a fellow woman passenger saw him working on an equation she thought was some special secret terrorist code and alerted the cabin crew.

Guido Menzio (40), an associate professor at the University of Pennsylvania, was taken off and questioned by agents in Philadelphia, after the woman next to him said she felt ill.

The Ivy League economist was flying from Philadelphia to Syracuse on Thursday to give a talk at Queen’s University in Ontario, Canada.

American Airlines confirmed on Saturday that a woman expressed suspicions about Menzio.