Get to Colorado this winter with a fare sale from Southwest Airlines! Southwest is one of the major carriers for the Denver Airport so what are you waiting for! Snag a flight into Denver and rent your vehicle with Switchback. For more info be sure to visit the Southwest Airlines special page. From the mountains to the ocean, get ready to start this winter off right with these low fares. So, pack your bags. What are you waiting for? Book by December 1, 2016 for travel in the U.S. November 29, 2016 through May 8, 2017. Travel to/from San Juan, Puerto Rico valid January 17, 2017 through March 2, 2017, and April 18, 2017 through May 8, 2017.