A Texas airport was evacuated Wednesday due to a bomb threat, after somebody telephoned alleging that three packages had been left inside a parking garage. About 2,000 passengers in the San Antonio International airport terminal were herded onto the runway for about 90 minutes after the unknown person called in the afternoon, warning about the packages. Flights were not allowed to land at the airport for more than two hours. No suspicious items were found in an intensive search, airport spokesman Rich Johnson said.