In addition, JetBlue and US Airways operate similar aircraft, A320s, in the United States, "adding to the cost synergies."
A combined US Airways and Alaska would be "very strong in Mexico and very well-positioned using Phoenix as a jumping-off point to other points in South America, as well as Charlotte, N.C., and Philadelphia," Becker said.
"Alaska is very tied in with Delta from Seattle to Asia. Of course, US Airways could get into that. Maybe then it makes sense for Delta and US Airways to get together with some carve-outs on the East Coast."
Airline mergers must undergo antitrust scrutiny, and the current climate in the Department of Justice could make megamergers in the future tougher to pull off.
"The United-Continental merger is not a done deal," said CRT Capital's Derchin. "I think it will be approved, but it's not for sure. Certainly, the Obama Justice Department is a lot tougher than the Bush White House on antitrust."
Might United-Continental come back in five years and try to acquire US Airways?
"You would run into the same antitrust concerns that were raised when United and US Airways first proposed merging" in 2001, said S&P's Baggaley. "Mostly around Washington, D.C., where US Airways has a significant position at Reagan National Airport and United at Dulles. It is possible because they are in the same Star Alliance. But I think United's combination with Continental makes that a good deal less likely."
Any merger scenario involving Continental would create anxiety in Cleveland, where the airline's hub at Cleveland Hopkins International Airport employs more than 3,000 people.
Talk of more mergers in the U.S. airline industry is heating up again as the major carriers recover from five years of extreme pain and more than $30 billion in losses.
The creditors are also demanding a new board for Delta that favors consolidation as a strategic option.
MINNEAPOLIS - Northwest Airlines and Delta Air Lines have held preliminary merger discussions, and the formerly private talks are now part of the high-stakes public battle over the future of Delta and...