In addition, stock prices have been buffeted by a wave of consolidation that has begun taking place; Southwest Airlines ( LUV ) recently announced that it will acquire fellow low-cost carrier AirTran Holdings (AAI), and United Airlines owner UAL Corporation recently merged with Continental Airlines to form United Continental Holdings ( UAL ), the largest airline company in the world. These deals have come on the heels of Delta Air Lines ( DAL ) acquiring Northwest Airlines in 2008, and they have helped underscore the fact that the entire airline industry seems to be embracing capacity discipline and is focusing on cost containment. In addition, investors ostensibly are pricing acquisition premiums into some of the remaining names in the space. Explosive Stock-Price Returns Holders of almost all airline companies have been rewarded nicely in 2010.