Here is another option - bookmark this link:

https://www.aa.com/homePage.do?locale=en_US

This might be better for those who experience this problem regularly because they are often outside the USA, as it takes you to the USA site even when you are abroad. I live in South America, but need to use the USA website since I'm paying with a USA credit card. If I just type in aa.com, I'm taken to my home country's site, but if I use the bookmark I go to the USA site. This eliminates the need to go cookie hunting or going through the reset process. I'm not sure if this will work for every country, but you might want to give it a try.