DALLAS (CBSDFW.COM) – A technical issue affecting Southwest Airlines flights across the country caused the airline to issue a ground stop early Monday morning.

A CBS 11 News crew was at Dallas Love Field Airport when hundreds of passengers lined up outside check-in. The company said the outage was “a result of a technology outage”.

When normal operations resumes the airline issued a statement saying  —

“As of 6:05am CDT, Southwest Airlines has lifted an internal ground stop implemented for about 40 minutes this morning during an outage with a vendor that services multiple carriers with data used in flight planning. Scattered flight delays are anticipated and Customers should check Southwest.com for the latest updates on specific flights. We’re working with Customers on any impacts to their travel plans and we appreciate their understanding as we place nothing higher than the safe operation of every flight.”

Delta Air Lines had also tweeted with customers about a “System-Wide Outage” that they were experiencing and that they were “working diligently to get it back up and running.”

The company later issued a statement that said, in part, “A brief third-party technology issue that prevented some Delta Connection flights from being dispatched on time this morning has been resolved. No cancellations are expected due to the issue.”

A spokesman for the Federal Aviation Administration said the issue involved a vendor that provides weight and balance software that airlines use to determine flight plans and make fuel calculations.