I was recently pick up by AA and I got this email today regarding my US Air App. I think the email is an effort to get all the hiring under one roof. I hear the company that handles US Air apps will now handle the AA apps. This all tells me that US Air process is going away and you will soon be in Dallas for an interview and it will be us to the needs of the Company whether you fly US Air metal or AA metal.
The red check next to the fit assessment has been hit and miss. I didn't retake my assessment (which was red for about 10 days) before I got an interview invite. I have heard others that said they did retake. I don't know if there is a correct answer for which path to take.