American West acquired US Airways. US Airways didn't change their name to American West (although America West adopted their purchase's better known name!). Now, it looks like US Airways is going to further merge into American Airlines, confusing.
US Airways was in bankruptcy in 2005; America West essentially took over US Airways, but then dropped its own branding and operated the merged airline as US Airways.
Last year American Airlines was in bankruptcy; US Airways essentially took over American, but is going to drop its own branding and operate the merged airline as American Airlines.
In the America West/US Airways merger, as I understand it there was never actually integration of the unions; they ended up in two groups, "West" and "East", and did not mix due to inability to agree on a merged seniority list ("East" was a larger group with more seniority by date of hire, but "West" didn't want to be effectively demoted by a straight seniority merge).
In the US Airways/American merger, meanwhile, it's the American Airlines pilots who are the larger group, but the US Airways pilots who would come out on top by straight date-of-hire merge. So that's going to be fun to work out.
And American's regional subsidiary Envoy (formerly American Eagle, renamed to avoid confusion with the umbrella brand for AA's regional services operated by multiple airlines) recently rejected a contract that would have brought new planes with a wage freeze, so AA is in the process of downsizing and threatening to downsize the Envoy subsidiary.
