the.com/icao codes
four letters that tell you exactly which runway you're about to miss.
means a four-letter code assigned by the international civil aviation organization to identify every airport on earth, unambiguously and forever.
from created after world war two as global air travel exploded and pilots needed a system less confusing than local airport names; the first letter usually marks the country or region, the rest narrows it down.
first letteroften signals country, like k for usa
not iatadifferent from the three-letter codes on your luggage tag
canada exceptionalmost all canadian airports start with cy
used by pilotsfiled in every flight plan, not just airport signage