The Dallas-based carried filed plans over the weekend to add four new routes and cut two others, as first seen in Cirium Diio schedules and later confirmed by a carrier spokesperson.

Beginning June 4, Southwest will add three flights from one of its newest bases, Nashville International Airport (BNA), as well as launch a new contender for the shortest route in its network. The new flights from BNA include daily service to Cincinnati/Northern Kentucky International Airport (CVG), Richmond International Airport (RIC) in Virginia and Greenville-Spartanburg International Airport (GSP) in South Carolina.

Of these routes, the one from BNA to GSP last operated in 2014; the others are all new to Southwest's network.

Southwest will also launch a new route from RIC to Baltimore/Washington International Thurgood Marshall Airport (BWI) on a twice-daily basis. When it begins, this 121-mile hop will become the second-shortest route in Southwest's continental U.S. network behind Denver to Colorado Springs, which measures 72 miles long, according to Cirium.

While the airline is making some noteworthy additions, it's not all good news for the carrier's network. This summer, it will scrap two routes: Atlanta to Little Rock, Arkansas, and Chicago O'Hare to Tampa.

Southwest explains that these modifications are being done "with a focus on serving the greatest number of nonstop markets, though in some cases we now will offer fewer frequencies in existing nonstop markets." (The Chicago O'Hare-to-Tampa route is currently scheduled to return during the peak winter holiday season.)