Southwest Airlines is adding about 15 daily flights, including nonstop service to six new markets, out of Dallas Love Field (DAL) in early 2019, crediting schedule-optimization for creating room to fly out of its already-crowded headquarters airport.

Under the revised schedule, daily nonstops will connect DAL with Charleston, Ft. Myers/Naples, Jacksonville, Louisville, Milwaukee, Minneapolis/St. Paul, and—in a seasonal-service addition—Panama City Beach, Florida. The airline also is adding Sunday-only service to Tucson. The Louisville and Tucson routes are new, while Minneapolis is being upgraded from Sunday-only and the others are former seasonal routes. The carrier is also adding frequencies on eight current DAL routes.

Among other changes, Southwest is bringing back its Newark-Nashville nonstops and stopping its Newark-Indianapolis flying. The changes go into effect Jan. 7, 2019.

"This is a re-optimized schedule, and as our unique optimization system is improved and enhanced, it allows us to implement significant changes to our network," the carrier said on its blog. "Our current schedule optimization toolset is generating returns with every schedule publication, allowing Southwest to capitalize on minute-by-minute time savings and adjustments and to operate even more flights out of its gates at Love Field," a carrier spokesman added.

The changes increase Southwest's peak daily DAL operation to 195 flights, up from 180. Southwest operates out of 18 gates at 20-gate DAL, and generally considered 10 flights per gate per day to be maximum capacity.

One of its gates is shared with Delta Air Lines in a long-running dispute that ended up in court, with Delta believing it should have more space for competition's sake, and Southwest arguing that its lease permits it to full use of its gates. Southwest also points out that under the five-party agreement, it cannot serve both DAL and Dallas-Fort Worth (DFW), meaning its only practical expansion avenue in the market is growing at DAL.

The latest changes do not affect the Southwest-Delta legal battle. Southwest is not adding service at Gate 15, the space it shares with Delta. In a court filing, Southwest said that if not for Delta's presence at Gate 15, it would add five more daily flights, but the court has ordered Southwest not to disrupt Delta's DAL operation until the legal proceedings are complete. Alaska Airlines occupies DAL's two remaining gates.

Southwest's schedule update also does not include any more details about the carrier's planned Hawaii service. Southwest has announced the markets in both Hawaii and the mainland U.S., but has not released a start date, schedule or city pairs.

Sean Broderick,