FILE PHOTO: A Spirit Airlines A320-200 airplane sits at a

FILE PHOTO: A Spirit Airlines Airbuys A320-200 airplane sits at a gate at the O’Hare Airport in Chicago, Illinois October 2, 2014. Incoming stormy weather and operational problems caused by a fire last week at a Chicago-area air traffic control facility forced the cancellation of nearly 750 flights on Thursday at Chicago airports. REUTERS/Jim Young