DALLAS (CBSDFW.COM) – Flight delays and passenger frustration after a computer issue grounded Southwest Airlines flights at some airports early Friday morning.

By midmorning some 600 Southwest flights had been delayed — about 15 percent of the airlines schedule.

Customers began complaining on Twitter about delays and not being able to book flights or get certain information online.

The Federal Aviation Administration (FAA) issued an alert about the problem and spokesman Lynn Lunsford sent the following statement to CBS 11 News around 6:30 a.m. —

“According to my information, the company briefly had some issues with a computer system that automatically uploads flight plans to the FAA. The situation was resolved about an hour ago.”

Southwest issued a statement later Friday morning that said, in part, “We are working directly with our customers who were impacted by average delays of 40 minutes in our earliest departing flights in the East.”

Initially, passengers believed a number of flight cancellations were related to the computer software issue, but Southwest said the approximately 80 cancelations on Friday were due to winter weather.

Officials at Dallas Love Field Airport said they had no planes operating when the “network operations” computer issue occurred so travel at the airport was not affected.

This morning’s technical problems were just one in a string of issues for the Dallas-based carrier. Over the last few days Southwest has been forced to cancel hundreds of flights either because of a maintenance “operations emergency” that the airline recently declared or because of winter weather happening across the country.