United Airlines has grounded flights nationwide on Wednesday night due to an issue with its weight and balance computer system.

United Airlines flights on major routes were grounded Wednesday because of a technology issue, and additional flight delays were expected into the evening, the airline said.

United Airlines flight schedules are slowly returning to normal after a nationwide technical issue forced flight cancellations and delays Wednesday night. Residual delays and cancellations continued Thursday morning for United Airlines flyers at Chicago's O'Hare International Airport after one of the airline's computer systems went down Wednesday night,