There are two terminal buildings in the Cancun airport. The terminal # 1 receive commercial flights like Mexicana, Aeromexico, Delta, Continental, American, US Airways,Varig, Martin Air, Air Canada, etc.
The terminal # 2 called FBO is exclusive for charter flights and private flights arrivals, if you are travelling to Cancun in a charter flight, that is the terminal where you will arrive and depart.
Transfer Between Terminals
An airport shuttle service runs between the main entrances to the terminals.

