American and US Airways are in the final stages of their merger. The Dividend Miles program has already been merged into the AAdvantage program, and the two airlines are already on a single operating certificate (meaning they’re one airline as far as the FAA is concerned).
The last major step is that the two airlines need to merge their reservations systems. American and US Airways will be merging their reservations systems on October 17, 2015, though there’s quite a bit leading up to that.

Here’s a summary of how that will go down:
- American and US Airways will be transitioning onto a single reservations system as of October 17, 2015
- That means as of October 17, 2015, US Airways flights will no longer exist — all flights will have American flight numbers, even if they’re operated by (former) US Airways planes
- As of mid-July, American has begun transferring US Airways reservations for travel on or after October 17 to American, so flight numbers for travel as of October 17, 2015, should progressively be changing
- There’s nothing you need to do during the process other than be patient, as transferring an unimaginable number of reservations will take time
Anyway, while you’d expect that US Airways’ website might not necessarily support bookings for travel as of October 17, 2015 (given that the airline will officially cease to exist), it seems that US Airways’ website isn’t supporting bookings for travel before that date either.
US Airways’ website is now redirecting all reservation requests to aa.com.

Historically there a couple of issues with making US Airways bookings on American’s website, though:
- Fares can differ significantly when booking a codeshare flight vs. a flight with a “native” flight number
- You can only upgrade day of departure when booked on a codeshare, while if you booked a US Airways flight with a US Airways flight number you could upgrade at the “standard” upgrade window of up to 100 hours out

The good news is that American’s website is now displaying US Airways “prime” (non-codeshare) flight numbers. If you want to book a US Airways flight on American’s website, go to the front page and click on “Refine your search.”

On the next page check the “All Carriers” box under the “Choose a Carrier” heading.

When you do this, American’s website will display US Airways prime flight numbers as well. However, these flights will be displayed last, so it might require some scrolling. That’s right, doing a search will show you the same flight twice — once as a codeshare, and once as a “prime” flight.

This is a bit tricky, and I assume many people will get screwed by this change as a result of booking codeshares rather than prime flights. That being said, if anything it should increase the upgrade odds for those of us in the know. It could very well be that American is in the process of removing US Airways codeshares from their website altogether, given that this change was literally just made.
Bottom line
Practically speaking, nothing is really changing here. You can still book US Airways flights under their “prime” flight numbers on American’s website. And you’ll want to be sure you do that, so you don’t accidentally jeopardize your upgrade by booking a codeshare flight.
(Tip of the hat to Pizza in motion)
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