It`s a small part of a huge trend that`s affecting how more than 660 million domestic air travelers fly every year.
Fourteen years ago, the United States had 10 major domestic airlines. Now, the competing major carriers have merged into four: American, Delta, Southwest and United.
Together, they control about 87% of the domestic market, MIT`s International Center for Air Transportation said.
Is that a good thing for travelers looking for lower airfares?
"I don`t think it`s bad at all," said Brett Snyder of airline industry blog The Cranky Flier. "Fares have come down lately. You still see these guys fighting with each other. But is there as much competition as there was? No, of course not, because there are fewer carriers."
Snyder, who spent more than a decade working for United, USAir and America West, called it "rational competition" among "smarter airlines" that know how to make a profit. "I guess from the customers` standpoint, you could argue that it would be better to have 20 tiny airlines losing money and taking you places cheap. But that`s not sustainable."
Infographic shows airline mega-mergers
Folks who think airfares are too high may be interested to know that domestic air travel is 17% cheaper in inflation-adjusted dollars than it was more than 20 years ago, according to federal statistics. But we also have to pay extra on some carriers to check bags and get seat assignments, which used to be included in the price of a ticket.
Also notable is that the Justice Department is investigating "possible unlawful coordination" of seat availability by airlines, allegedly to prop up ticket prices.
More about: