The International Civil Aviation Organization (ICAO) is a United Nations agency which helps 193 countries to cooperate together and share their skies to their mutual benefit.
Do pilots use ICAO?
Pilots, as well as air controllers, use the ICAO code in their day to day as there are never two identical ICAO codes. Additionally, once you know how the code is made up, you can find out, without a doubt, which airport youre flying to.