Definition
KLAX is the four-letter ICAO location identifier for Los Angeles International Airport, a major Class B airport on the coast of Southern California. The same airport is identified as LAX in the FAA's three-letter system and in airline use; KLAX is the form used in flight plans, ATC computer systems, and international flight planning.
Plain English
KLAX is the official code for Los Angeles International Airport when filing flight plans or working with air traffic control systems. It's the same airport people call LAX — the K just means it's in the contiguous United States.
Context Anchor
You will see KLAX on charts, in flight plans, in aviation weather reports, in instrument procedure titles, and in cockpit navigation systems when referring to Los Angeles International Airport.
Derivation
The 'K' prefix is assigned by ICAO to airports in the contiguous 48 United States. 'LAX' is the original three-letter identifier for Los Angeles, kept as the last three characters when the K was added to make it ICAO-compliant.
Why Pilots Care
When filing IFR flight plans or programming an FMS or GPS, you almost always use the four-letter ICAO identifier (KLAX), not the three-letter version (LAX). Mixing them up can cause flight plan rejections or routing errors.
Intuition Check
Do not treat KLAX as the airport name itself or as a word to interpret. It is an identifier: a short code that points to Los Angeles International Airport.
Example Sentence 1
The crew filed KLAX as the destination on their IFR flight plan from Honolulu.
Example Sentence 2
The crew reviewed the latest weather for KLAX before departure.