PITTSBURGH, Pa. (WPXI) — Long lines of cars backed up. Growing numbers of delayed or canceled flights. A thick, heavy fog blanketed the region on Christmas Eve, and the travel headaches continued well into the evening. As of about 9 p.m., there were over two dozen canceled flights into and out of Pittsburgh International airport. A Dense Fog Advisory had been issued by the National Weather Service, effective until late morning on Christmas Day. At PIT, drivers were lining the roads leading to the terminal waiting for their loved ones to arrive. Buses were dispatched from Cleveland and Dulles airports to bring passengers to Pittsburgh after their flights were canceled. One man’s flight from Dulles airport to Pittsburgh was canceled, so the airline put him on a bus to get him home in time for the holidays.