First, AA will set up an automated phone interview with you. They notify by email letting you know you have gotten to that step, then you call the number provided. You will be asked 5-6 questions and given 3 minutes to answer each. They are all customer service questions, and some are situational.
Next, you will receive an email asking you to come to an in person interview in Dallas. It took about 3 weeks for me to get that email. After calling the number provided they will schedule an interview in DFW about a week out.
The interview experience was the best I have had yet with any airline. I have interviewed with two other major carriers (one I didn't get, the other I did but ultimately turned it down), and AA is by far the nicest bunch of folks out there. There were about 15 candidates there and it took about 4.5 hours altogether. The AA reps are welcoming, friendly, excited to be hiring, and just all-around a great group of people. You will have group interactive exercises, a small interview group with about 4 candidates and two reps, as well as a short one-on-one interview. All the interview questions are customer service related and many are situational, so be prepared to talk about specific instances where you have done out of the ordinary things for customers, or for your community in general.
Not at any time were the interviewers confrontational or negative. They genuinely want to get to know you and see your real personality. I cannot reiterate enough how nice these people were. It was a very good experience, and I would have said that regardless of whether or not I got the job.