Southwest Airlines unveils date to begin Fresno service. Here's where they will be flying Fresno Bee 1/22/2021 Tim Sheehan, The Fresno Bee Jan. 21—Southwest Airlines will enter the Fresno air travel market in April with daily nonstop round trips to Las Vegas and Denver. The airline, which has long been coveted by Fresno city officials and Valley travelers, officially unveiled its plans Thursday, about a month after initially announcing its intention to begin flights to and from Fresno Yosemite International Airport. The two routes will start on April 25. Southwest will fly one daily round trip between Fresno and Denver, and three daily round trips between Fresno and Las Vegas.