Meyer Professor of Middle East History E. Roger Owen was already flying from Europe toward Boston when his flight was diverted to Halifax, Nova Scotia, where he has remained since Tuesday.

“Students might not know how to deal with this,” said Ahmed Jebari, a staff assistant in department. “Students are shopping, and if they don’t know the professors, they might not take the class.”

A number of travelling students hoping to return to campus for registration Tuesday were also forced to alter their plans.

Last night at about 8:30 p.m., Samuel Graham-Felsen ’04 sat on a cruise ship traveling from a port near Halifax, Nova Scotia, expecting to return to school early this morning.

Graham-Felsen spent last weekend in Paris and boarded a plane traveling back to Boston on Tuesday. About halfway into the flight, the pilot announced that the plane would have to land in Halifax because of “some kind of terrorism,” Graham-Felsen said.

“I just assumed there was some bomb threat at the airport or something,” he said.

But when the airplane landed in a sea of planes lined up at the Halifax airport, Graham-Felsen said he decided to call his roommate, Justin A. Erlich ’03.

“I told him I was stranded in Canada and asked what was going on,” Graham-Felsen said. “When I heard, I was like, ‘Oh my God, oh my God!’”