Southwest Airlines’ proposed $1.4-billion acquisition of AirTran Airways reflects a fact of life for many low-cost carriers: They may be reaching the end of their ability to grow organically.
Most analysts believe the U.S. Justice Department will decide not to oppose the acquisition, given the small overlap between the carriers, although the government’s response is not always predictable and there are some things that make this merger different than those of Delta Air Lines with Northwest Airlines and United Airlines....