Maybe next year: two houses divided against themselves cannot merge, and it's a good question if they can stand. That's the parable of the two airlines that have been trying to mere since the year 2000, when United parent UAL and US Airways made their first moves toward each other. They've been dancing since then but and have come close to touching cheeks, but, no, it's no tango. The latest is that it's officially off, with Doug Parker, the US Airways chief, telling his troops, "It is simply unlikely that anything will happen in 2008 as our industry continues to struggle with how to function in a world with $130 a barrel oil prices." Glenn Tilton, the boss at United, said United would "size the business appropriately, leverage our capacity discipline to pass on commodity costs to customers, and accelerate development of new revenue sources."