The use of the Metropolitan area airport codes is to identify specific airports. For example if you say that your airport of destination is the London Airport, there are several airports located in London, or there are can be an airport named after that but is located in the United States. To eliminate confusion in using a general term to address specific airports, this is where the metropolitan area airport codes come into play. By using these location identifiers, you will be able to know specifically which airport you are bound to.
There are four systems used with location identifiers.
- International Air Transport Association (IATA) – the main focus of this location identifier is on commercial airports. It groups about 270 airline carriers in which it flies over 95% of the entire international air traffic. All the codes under the IATA are combined with 3 letters such as JFK which stands for the John F Kennedy International Airport, hence coded as IATA: JFK. Fifty combination codes are reserved but not available for the assignment to the airports.
- International Civil Aviation Organization (ICAO) – these are location identifiers allocated by the national government through ICAO to airfields, airports or any other facilities. The codes are a combination of 4 letters such as the LIRF in which the first 2 letters stands for the region and the country – L for Lazio while I is for Italy, R for Roma and F for Fiumicino thus this identifies the Roma Fiumicino Leonardo Da Vinci Airport in Lazio, Italy.
- Federal Aviation Administration (FAA) – used to identify manned ATC facilities, weather stations, navigation aids and airports that are within the US. The code is a combination of 3 letters but only assigned to airports that has passed through its criteria.
- Transport Canada – from the name itself, this identifies transportation facilities within the jurisdiction of Canada. The codes are a combination of 3 letters or 2 which is followed by a number. The former starts with the letters Z or Y and the latter starts with any letter other than the Z, Y, X, W, V, U, R, Q, O, M, L, I, H or G.
Metropolitan area airport codes are mostly ignored but they can be a very helpful tool to indicate the kind of flight you are going to get, especially during connecting flights. This way you will be able to know the specific airport for inbound and outbound flights.