Just because you had a passport at a certain point in time doesn't mean you still have it - even well before the expiration date. For example, you may have run out of pages and since they won't add pages any longer, you would get a new passport. You could have lost your passport. You could have changed your name. As annoying as entering the information is, I think that AA is trying to protect itself and get your most current information since what you have on file may not be accurate.