We went through AEP three times in the last month on our Argentina trip - the airport is well-organised now. There's no priority checkin for people with OW status but there is a priority checkin for people who have checked in on LAN.com, and that queue was consistently much faster. So definitely checkin online if you can (don't know how you'd do that on an AA booking) since that will ease your way through. There was only a security queue one out of the three times we went through and that delay was only a few minutes on that occasion. Nonetheless, it's an unfamiliar airport and Argentine logistics can sometimes be interesting. I'd have said 1.5 hours if you check in online and have your boarding passes, otherwise 2 hours.