I don't think SWA has any desire to go international other then Central and some South America. There business model just does not support that type of operation. No quick turns and all the hassles plus costs of flying international. With their employee costs they would have a tough time competing. Having your aircraft tied up for hours awaiting customs clearances is not something they would tolerate well let alone positive bag match and the extra personal required to staff rechecking baggage and other issues in customs..