The busiest commercial air carrier at Harry Reid International Airport will expand flights and destinations from Las Vegas over the next year, Southwest Airlines announced Monday. Among the new offerings will be Southwest’s previously announced first nonstop international flights to Mexico and a daily round trip to the company’s newest and northernmost destination, Anchorage, Alaska. The Dallas-based carrier is adding nonstop flights from Las Vegas to 11 destinations as well as more flights on 15 existing routes. The expansion is a part of Southwest’s initiative focusing on two of its highest rated destinations, Las Vegas and Orlando, Florida. “Las Vegas and Orlando are foundational communities in our network and places where Southwest long has offered the most service, seats and nonstop travel options,” said Andrew Watterson, Southwest’s chief operating officer.…