Every large U.S. airline is reportedly in talks with another carrier for a possible merger. What the final route map will look like remains pretty unclear.

Ever since Delta Air Lines and Northwest Airlines began merger talks in January (the two announced a deal on Monday), the industry has been abuzz with who’s-talking-to-whom. Continental and United have laid major groundwork for a merger and could move ahead “pretty quickly” with a deal, sources have told Reuters.

A merger between United and Continental, the second and fourth-largest U.S. airlines respectively, would surpass a Delta-Northwest combination as the world’s largest carrier.

Some reports say that United Airlines has also been in talks with US Airways about a potential merger. And it’s not just media reports: executives are also publicly dropping hints of the need to merge.

In a message to US Airways employees today, CEO Doug Parker reiterated his long-held opinion that the industry is too fragmented and that mergers would produce a “much healthier industry” that would benefit employees and passengers.

Continental CEO Larry Kellner, who has always said the airline would like to remain independent unless the competitive landscape changes, on Tuesday said the Delta-Northwest merger “will change the competitive landscape for Continental and the entire airline industry” and added that Continental will review strategic alternatives to ensure it remains a strong long-term competitor.

After racking up $35 billion in losses and finally emerging from a five-year slump in 2006, U.S. airlines are hoping that mergers could lead to higher fares as combined carriers reduce flights and use their increased market power to raise prices.

The airlines also face a renewed sense of urgency to consolidate and cut costs amid skyrocketing fuel prices, a weak economy and a growing competitive threat from European carriers as trade barriers fall on trans-Atlantic travel.

And even though Delta and Northwest have agreed to a deal, they aren’t being spared the buzz. There is now talk of American Airlines, currently the largest carrier, possibly making a counter bid for Northwest. Calyon Securities analyst Ray Neidl said in a research note: “They’d [American] be a good fit for either Delta or Northwest, and I don’t entirely rule out them coming in as a spoiler. I’m not predicting it, but it’s a possibility.”

United and US Airways tried to merger in 2001, but the deal was blocked by the U.S. Department of Justice. Then, in 2005, America West acquired US Airways.

That was not the end of it: US Airways also proposed a merger with Delta Air Lines in 2006, but was fended off by creditors and the pilots’ union.

Confused? Join the club. There are definitely more mergers to come in this industry. And they will likely come in quick succession as airlines rush to get these deals approved under the Bush administration, considered to be more merger-friendly.

For the final route maps, just belt up and sit tight. Shouldn’t be too long a ride.