Despite the pleas by employees [2] to preserve their airline, there's no guarantee that Frontier [3] as we know it will continue to exist. Dallas-based Southwest Airlines has until 10 a.m. this morning to submit its formal $113.6 million offer, a few million more than what Republic Airways Holdings has put up. If successful, Southwest would eliminate a major competitor at Denver International Airport and gain flights in markets that include Mexican resorts, according to The Denver Post [4]. As aviation analyst Mike Boyd of Boyd Group International in Evergreen points out, Frontier has given Southwest "a bloody nose and a lot of heartburn" since Southwest entered the Denver market three years ago. Meanwhile, if Republic gets Frontier, Bill Swelbar, a research engineer at the Massachusetts Institute of Technology's Center for Air Transportation says it would create "overnight, a new, potentially threatening competitor to Southwest's domestic dominance." The Houston Chronicle [5] writes that Southwest seems to want Frontier to prevent anyone else from buying it. And The Street [6] opines that Southwest's bid "may be viewed as a sign of its failure" in the market.