Ramifications of Tuesday’s tragic attacks continued to be felt on campus yesterday, with faculty and students unable to return to Harvard because of continued widespread airport closings.

Logan International Airport remained closed yesterday and six members of the physics department were trapped in cities from San Francisco to Dusseldorf—resulting in the cancellation of the semester’s first physics classes.

Students who set their alarms early to attend Physics 1a at 8:30 yesterday morning found the doors to Science Center B closed, with Professor of Physics David A. Weitz searching for a return route from France.

Mallinckrodt Professor of Physics Roy J. Glauber planned to fly from Dusseldorf, Germany to Boston Tuesday in time to interview for Freshman Seminar 30, “Science and Technology,” on Wednesday, but has been trapped at London’s Heathrow Airport instead.

Gerard F. Denault, associate director of the Freshman Seminar Program, said his office has told students interested in the class to “hold on” until Glauber returns. He said add/drop fees will be waved for students who sign up late for the class.

Denault also filled in Wednesday for the first hour of the informational session on Freshman Seminar 17, “Public Policy Approaches to Global Climate Changes,” as Boas Professor of International Economics Richard N. Cooper arrived late from Washington, D.C.

“I was at a meeting in Washington and I was supposed to fly back Tuesday,” Cooper said. “Instead I rode a train in the afternoon and got to class half way through.”

Four other physics faculty members are watching the news and struggling to find flights home from cities in California.