United Airlines said it expected "minimal impact" to Monday flights after a computer issue caused the airline to ground all domestic flights for 2½ hours Sunday night.
United said more than 200 flights were affected Sunday. On Monday, the airline said it planned to cancel a dozen flights, out of about 4,500 on its schedule, and expected a "small number" of short delays.
The problem affected the system the airline uses to send pilots information needed before flights can depart, such as weight and balance information, and there was no sign it was caused by a hack or security breach, the airline said.
A United Airlines jet taxis at O'Hare International Airport.