Southwest Airlines has canceled 1,150 flights since the airline's full ground stop for on Wednesday. The trouble started with a "system outage," and the ground stop lasted for just over an hour.
The system came back up later Wednesday afternoon, but hundreds of flights were backlogged, and that continued to affect the airline all day Thursday.
Southwest did say its operations are "stabilized and performing normally throughout."
"Our Employees in airports, online, and on the phone are assisting customers in large numbers and that is taking longer than average," the company said in a statement. "In the midst of peak summertime travel, we recognize many flights through this weekend were already close to full and we recommend customers who have flexibility explore re-booking on alternate dates."