A "Category 1" (Cat 1) rating does not actually refer to an individual airport, but rather to a country's aviation safety oversight as determined by the FAA's International Aviation Safety Assessment (IASA) program. A Category 1 rating means that a country's civil aviation authority has been found to meet the international safety standards set by the International Civil Aviation Organization (ICAO). This rating is crucial because it allows airlines from that country to establish service to the United States and carry the codes of U.S. carriers. In 2026, the assessment focuses on eight critical elements, including personnel licensing, aircraft operations, and airworthiness. If a country falls to Category 2, it means their oversight is deficient, and their airlines are restricted from expanding U.S. routes. On a separate technical level, "CAT I" (Category 1) can also refer to an Instrument Landing System (ILS) at an airport, which allows pilots to land in low-visibility conditions with a decision height of 200 feet and visibility of at least 2,400 feet.