Heavy fog forced cancellation or delays of hundreds of airline flights Thursday in the Midwest and Northeast, stranding travelers and leading to a "big old slumber party" at Chicago's O'Hare International Airport.
About 30% of O'Hare's average 200 arrivals and departures each hour were canceled and all flight operations were suspended at the smaller Midway Airport, Chicago Aviation Department spokeswoman Lisa Howard said.
Traffic at the three major airports in the New York-New Jersey area was disrupted, with Newark and La Guardia hardest hit.
Arrivals were suspended for several hours at La Guardia until early afternoon, when the fog began to lift, said the Port Authority, which runs the airports.
Fog also caused delays or cancellations at Boston's Logan International Airport, Rhode Island's T. F. Green Airport, Milwaukee's Mitchell International Airport, and in Detroit at Metropolitan Airport and Kent County International Airport.