Mariscal Sucre International Airport
Facts on UIO
Quito's airport code isn't QUI because IATA/ICAO reserve codes starting with 'Q' for other communications purposes, so the airport pulled from the remaining letters of 'QUIto' to form UIO.
Source: Air-Port-Codes
The airport is named for Antonio José de Sucre, a South American independence leader known as the 'Mariscal' (Marshal), who fought alongside Simón Bolívar.
The current Mariscal Sucre International Airport opened in February 2013 in the Tababela valley about 18 km east of Quito, replacing a 53-year-old in-city airport that had become too dangerous and hemmed in by mountains to expand; the new airport was rated the first 5-star airport in the Western Hemisphere by Skytrax.