American Airlines told employees today that US Airways will effectively disappear on Oct. 17, when the combined airline moves to a single reservations system.
American has done well with merger integration so far, and I know it has considered just about every scenario with regard to combining the two airlines. But you can probably expect that flying American during the Oct. 17 will be a bit difficult. United's March 2012 reservations system cutover was a mess, though American's likely will be better, if only because it probably learned from United's missteps. Still, you might plan for delays.
One interesting thing about the cutover. As noted in the bottom left-hand corner of the graphic, American is proactively canceling some flights for that weekend. It's also going to make sure some flights don't fly full. Fewer passengers should mean fewer problems.
Here's the plan for Oct. 17, straight from American's employee newsletter.