In the latest schedule update, Southwest Airlines disclosed 25 new and returning routes. While some were previously announced, others were not. The development came as the self-described hybrid operator removed what was to be its longest-ever international operation.

Various other US operators have unveiled additional links or network changes. For example, Delta Air Lines has officially revealed that it will fly between Los Angeles and Manila, while United Airlines will relaunch service on four routes from Newark and JetBlue has adapted its operations to Amsterdam.

These 22 Domestic Routes Will Commence

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They are summarized in the following table and shown on the interactive map. As some of the airport pairs will only exist for Spring Break, those links will have few flights and a short operating period.

The most notable addition is the ultra-short link market from Baltimore/Washington International Thurgood Marshall Airport (BWI) to Philadelphia International Airport (PHL), which was made available last week. This will, of course, focus entirely on passengers connecting elsewhere, especially via BWI, which is among Southwest’s most-served airports. More on this market later in this article.

Schedule analysis using Cirium Diio data shows that 12 of the following 22 domestic markets (55%) have not previously had nonstop flights with Southwest. They include all three additions from Nashville International Airport (BNA), which is becoming an increasingly critical airport, including for connections, in Southwest’s network. Even more significantly, three of the 12 entries (BNA to St Thomas and Wichita and Milwaukee to Panama City) have not had nonstop flights by any airline before.

Southwest Will Begin These Three International Links

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On March 13, Southwest will lift off from AUS to San José (Costa Rica), becoming the first time that that market has had nonstop service. Flights will operate on Saturdays, leaving Texas at 10:25 AM and arriving back at 7:20 PM. The same 737 MAX 8 is scheduled to operate both legs. Booking data shows that AUS was the US’s fourth-largest unserved market to the capital of Costa Rica.

Then there’s BNA to Aruba (begins March 13; Saturday only) and John Glenn Columbus International Airport (CMH) to Punta Cana (starts March 13; Saturday only). Both markets are new to Southwest’s network, and BNA to Aruba has not had flights by any carrier before. However, the US Department of Transportation (DOT) shows that CMH had service to the ever-popular destination in the Dominican Republic in 2004, when the now long-defunct USA 3000 operated.

A Quick Look At BWI To PHL

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At just 78 nautical miles (144 km) each way, BWI to PHL is among the most intriguing additions. It is, of course, fully about transit traffic. Southwest is increasingly adding many very short services for this purpose, as connecting passengers become a bigger target. Indeed, between now and next April, the airline has scheduled four routes covering no more than 78 nautical miles and 14 within 130 nautical miles (241 km).

The airport pair was last served by American Eagle in 2020 to feed American Airlines’ ex-US Airways PHL hub. In the past, it was in the hands of US Airways itself, which, in the more distant past, also had a hub at BWI. In the past 20 years, Cirium data shows that up to 11 daily departures were available.

Given the very short distance between Greater Washington DC and Philadelphia, it is surprising that the DOT shows that 25,586 local passengers flew between airports serving those areas in the 12 months to April 2026. They did not go elsewhere. Ronald Reagan Washington National Airport (DCA) to Philadelphia had the most local traffic (14,684 passengers).