Southwest Airlines will compete with fellow low-cost operators AirTran Airways and Midwest Airlines when it launches service at Midwest's hub in Milwaukee, Wisconsin later this year.
Dallas-based Southwest has not detailed specifics about its fourth new destination for 2009 except that it will offer multiple city pairs.
Service from General Mitchell International airport will begin after Southwest inaugurates operations from New York LaGuardia airport on 28 June and from Boston Logan International airport on 16 August.
Southwest's arrival comes as AirTran has been bolstering its Milwaukee operations by roughly 57% year-over-year as it vies with former takeover target Midwest.
But even with its latest network offerings, Southwest maintains its plans for zero fleet growth in 2009 and 2010.