How does this work? Is this included in your ticket (I booked through Orbitz and flying with AA) or do you need to pay for that separately?
It's almost certainly included with your ticket, since you're flying AA. However, most people flying from the UK have to pay it separately on departure.
I have always flown AA and it was included. This time I flew Jetblue no mention was made of the departure tax until we landed in Cancun when we were handed a tiny slip of paper along with all the other papers they hand you getting off the plane. It stated as of June 2009 that Jetblue passangers will be charged the 20$ departure tax when they check in for their flight home! Nice eh! I asked others at out hotel and no one on other airlines got this treatment. I let Jetblue know when I got back that I consider it unethical not to inform passesgers of this tax collection untill they get to their destination. Sure does make it hard to compare airfares when they play theses games. I will go back to using AA in future
