The cost of taking a 'Taxi Autorizado' from the airport into Mexico City keeps going up. I have the following tip in my guidebook, but for those of you you don't have the book, or missed it, here it is again. My neighbor who works for Aeromexico told me all the airport workers use this.
If you arrive in Terminal One, there is a taxi sitio with metered cabs. It is near Sala D between Puertas 5 and 6. Take the escalator up and cross the bridge--it is where the Aerotren stop is located. Go down the stairs at the far end of the bridge--the taxi sitio is across the street. I just returned home from Merida today and my taxi ride was less than half what a ticketed cab ride would have cost.
The taxi driver told me that sitio cabs are not allowed to drive into Terminal Two. However, he claims there is a sitio dispatcher on the street in front of the airport who will call you a cab from Terminal One.
You can also take the Aerotren (monorail) between the two terminals--but you must show a boarding pass to get on.
Caution: In no case should you go out on the street and try to flag down your own cab!
P.S. this was added by one reader: