More flight delays could be in store today in Houston and other cities as a result of a power outage that shut down the Atlanta hub on Sunday. An underground electrical fire caused the power outage at the Hartsfield-Jackson Atlanta International Airport at about 1 p.m. The Federal Aviation Administration ordered all flights headed for Atlanta to be held on the ground at their departure airport. The Atlanta airport handles flights for Delta and Southwest, which both operate at Hobby. Bush Intercontinental Airport was less affected by the outage. The outage also caused delays at airports in Dallas and San Antonio.