According to the airline, Southwest "began experiencing intermittent performance issues earlier Wednesday afternoon with multiple technology systems as a result of an outage.''
Twenty-six departures from Lindbergh Field and 10 arrivals had been delayed, according to airport officials. Southwest departures from Los Angeles International Airport were also being delayed, airport authorities said on Twitter.
As a result, the airline issued a "ground stop'' for all flights that had not yet left the gate. Many passengers took to Twitter to complain of extensive delays.
The ground stop was lifted around 1 p.m., but delays were expected to continue throughout the day as the airline worked to get flights back in the air.
"We apologize to our customers whose travel plans are impacted,'' according to the airline. ".. We expect to continue our move toward a normal operation but believe it will take time.''