DALLAS — Southwest Airlines flights across the country were held up Wednesday while the airline worked to fix technology problems.

Southwest began having intermittent problems with several systems after an outage.

“We are now managing flight delays across our system, with a temporary ground stop in place for those flights that have not left the gate,” spokesman Brad Hawkins said in an emailed statement.

For about three hours, visitors to Southwest.com couldn’t buy tickets, check in for flights, or check their flight’s status.

Hawkins said that systems were gradually coming back, but that it might take time before the airline could resume normal operations.

Anxious customers tweeted to Southwest that they could not check in for flights.

By about 5 p.m. Central time, Southwest had canceled 16 flights, more than any other U.S. carrier, and delayed 245 others, according to tracking service FlightAware.com.

Airlines have sprawling, overlapping and complicated technology systems, and even brief outages can cause thousands of passengers to be stranded for hours.