Too much logic. As long as some MBAs and lawyers can drain some money out, it's possible.US Airways is in trouble. With United/Continental merging, there's a good chance that they'll get squeezed out of the Star Alliance, just as Continental got squeezed out of the Sky Team Alliance when Delta and Northwest merged.
US Airways also has the problem of significant route overlap with Delta, United, and AMR which would make any merger 'troublesome'. While Northwest/Delta and Continental/United had some route overlap, it was less than what US Airways will be facing. And route overlap means that the combined airline will have to shrink.
US Airways is in the very difficult position where they're not big enough to survive standalone in a worldwide alliance and they're not small enough to be a geographical niche player (Alaska, Hawaiian, Spirit).
I think that their best bet is to eventually get merged into AMR. The big problem is that Parker still hasn't integrated US Airways and America West. Parker needs to get US Airways' house in order before anyone will want to merge with US Airways. The only CEO dumb/greedy enough to have courted US Airways was Tilton.
As far as US Airways taking over AMR, I just don't see it.