Task: Question Generation
Input (English): Mexico City is served by Mexico City International Airport (IATA Airport Code: MEX). This airport is Latin America's second busiest and one of the largests in traffic, with daily flights to United States and Canada, mainland Mexico, Central America and the Caribbean, South America, Europe and Asia. Aeroméxico (Skyteam) is based at this airport, and provide codeshare agreements with non-Mexican airlines that span the entire globe. In 2014, the airport handled well over 34 million passengers, just over 2 million more than the year before. This traffic exceeds the current capacity of the airport, which has historically centralized the majority of air traffic in the country. An alternate option is Lic. Adolfo López Mateos International Airport (IATA Airport Code: TLC) in nearby Toluca, State of Mexico, although due to several airlines' decisions to terminate service to TLC, the airport has seen a passenger drop to just over 700,000 passengers in 2014 from over 2.1 million passengers just four years prior.
Output (English): What is the short hand code for Mexico City's largest airport?