A US Airways Group Inc. flight was diverted after an Orthodox Jewish teenager began praying and using a box which contains verses, setting off concerns among skittish crew members.

Nerves have been on edge after the so-called underwear bomber's attempt to blow up a flight over Detroit in December, adding to an atmosphere of caution that has prevailed since the terror attack of Sept. 11, 2001.

Just before 9 a.m. EST, the crew on a US Airways Express flight--operated by Republic Airways Holdings Inc.'s Chautauqua Airlines and bound from New York's LaGuardia Airport to Louisville, Ky.--decided to land in Philadelphia to address their concerns. J.J. Klaver, a special agent with the Federal Bureau of Investigation, said the 17-year-old unveiled a phylactery, a leather box worn during certain Jewish services and also known as a tefillin, early in the flight. The teen was accompanied by his 16-year-old sister.

That landing occurred without incident, and all 15 passengers on the plane were "reaccommodated." The teen was not detained or arrested. Klaver said, "This was just an incident."

A spokeswoman for the Transportation Security Administration said the agency was notified about 8:30 a.m. of "a disruptive passenger" before the crew diverted the flight. She also said the plane was swept, but that nothing was found.