Seems some airlines roll exit tax into originial ticket price charged and some charge and exit tax before you leave Mexico. It would be helpful to know your airlines position before you get to the airport to go home, to make sure you have the dough left over and to intellegently compare ticket prices. In my last 3 trips American and Mexicana Air did not charge exit tax. JetBlue gave us a TINY slip of paper as we arrived saying we would be charged exit tax before returning home. That tiny piece of paper was a joke as it could easily have been overlooked with all the forms you need to get out of the airport at arrivals. Please post your airline and if you were charged a separate exit tax at the airport.