And then there were three. Once completed, the latest airline merger, bringing together US Airways and American Airlines, will leave the nation's skies dominated by three major global airlines: United and Delta (both of which grew after their own mergers) and the expanded American.

The long-discussed merger — which will form the world's largest airline — came closer to reality last week when US Air and American reached a settlement with the Justice Department. Justice had been reluctant to approve the union, claiming such a giant would reduce competition. In the settlement, the airlines agreed to sell terminal slots to low-cost carriers at some of the nation's largest airports, from Washington and Boston to Chicago and New York.

How that plays out at Minneapolis-St. Paul International Airport remains to be seen. Delta currently carries 77 percent of the passengers out of the airport; US Airways claims 4 percent and American, 3 percent. Since Delta so clearly dominates, will there be any effect at all?

Airline analyst Terry Trippler, of www.the planerules.com, believes that there will be, because the new American will bring heightened competition to Delta.

As Delta downplays MSP as a hub, most Delta fliers in this market make a connection; only 40 percent fly directly to their destination. Trippler predicts that passengers will be asking themselves, why not stop in Dallas instead of Atlanta, or Chicago instead of Detroit? "Don't be surprised to see Delta add nonstops to fight off American," Trippler said.

As for ticket prices, they should hold steady rather than rise. But if the economy slumps even a little, look for deals. "There are these giant airlines," Trippler said, "and they will have lots of seats to sell."

Send questions to travel editor Kerri Westenberg at travel@startribune.com; follow her on twitter @kerriwestenberg.