DALLAS -

After four decades of expanding to all corners of the lower 48 states, Southwest Airlines flies into new territory on Tuesday - Jamaica, the Bahamas and Aruba.
    
Southwest is taking over routes flown by AirTran Airways, which it bought in 2011. The company plans to eliminate the AirTran brand by year end.
    
Southwest Flight 1804 left Baltimore-Washington International Airport on Tuesday morning for the airline's first overseas flight - to Oranjestad, Aruba. After the first three international destinations, it will add service next month to Cancun and Los Cabos in Mexico, and will start flying to Mexico City and Punta Cana in the Dominican Republic in November.
    
By late this year, Southwest will operate the flights from eight U.S. cities. Still, its foreign footprint will be tiny compared with rivals American, United and Delta, which fly to Europe, Asia and South America.
    
Southwest Airlines Co. carries more passengers within the U.S. than any other airline, but only about 1 percent of its passenger-carrying capacity is on international routes. That might not change much. CEO Gary Kelly said recently that international will be "a relatively modest component" of the airline's route system for the next several years.
    
Still, the international flying, plus expansion in New York, Washington and Dallas, are important as Southwest tries to regain momentum. In recent years, it has dealt with high fuel prices, a tepid U.S. economy, and tougher competition from both old rivals and newcomers such as JetBlue and Spirit.

"We have announced our international service through Nov. 2.  The US airports where we will be operating international service include Baltimore/Washington, Atlanta, and Orlando beginning July 1; Orange County and Milwaukee beginning August; and Austin, Chicago, and San Antonio beginning Nov. 2," Southwest said in a news release to ABC-7 inquiring about international flights being added to El Paso. "We are currently building international terminals at Houston Hobby and Ft. Lauderdale.  As we continue to look at the future of our international operations, we would look at cities from a variety of factors, whether that means a lot of Southwest flights, strong competition, and/or strong Customer demand - there is a lot of criteria that goes into city selection.  No additional cities either domestically or internationally have been announced. "

Southwest's traffic - the number of miles that passengers fly - grew by double-digit percentages from 2004 through 2006. It hasn't approached that kind of growth since, however, except in the year that it added AirTran. Last year, traffic grew just 1.4 percent, the second-smallest gain in this century.