空港コード

空港の名称はしばしば、IATAコードやICAOコードなど、長さが数文字しかないコードで省略されることがあります。コードを覚えると経路を考えたりチケット予約に役立ち、あるいは会話のタネに使えます。

IATA

国際航空運送協会 International Air Transport Association は空港用の3文字のコード（略号）と、主要航空会社ごとの2文字のコードを定義する。これらのコードは、発券やフライトの予約および手荷物タグに使うため、グローバルに一意である。

TLV^IATA行きの手荷物タグの控え

手荷物タグ（URA^IATA）はウラ（アナトリア）ではなく、カザフスタンのオラル（ウラリスク）行き。

旅行先の空港コードを知っておくと、次のように役に立つ。

• 一部の大都市は、都市自体または郊外に複数の空港があり、一例としてロンドンには国際空港が3つあり — ヒースロー空港 (英語版) （LHR^IATA）、ガトウィック空港 (英語版) （LGW^IATA）、スタンステッド空港（STN^IATA）— さらに国内線空港が3つ存在する。さらに、合計6つの空港すべてを代表する7番目のコードLON^IATAも設けてあり、ロンドン行きのフライトを複数、検索したいときは、一般にこれで検索するのが最善の方法である。
• 一部の航空会社は、小さな空港を大都市を折り込み、誤解を招く名称で呼んでいる。一例としてフランクフルト・アム・マイン（英語）よりもルクセンブルク市（英語）に近いハーン線 wikidata（英語）のチケットを、代理店は「フランクフルト行き」と称して販売している。ジローナ wikidata （英語）にはバルセロナのあるカタルーニャ州北東部海岸との共通点がほとんどなく、ヴィーツェ（英語）は昔、「デュッセルドルフ・ヴェーツェ空港」と称したが、実際には離れすぎている点を根拠にデュッセルドルフを名乗らないよう、裁判所命令を受けて改称している。
• 同名の都市も複数ある。アメリカのメイン州ポートランド（英語）に由来する同名都市（英語）は大陸の反対側、西海岸にある。同じニューサウスウェールズでも、オーストラリア（英語）とノヴァスコシア（英語）とでは赤道を挟んで南北に位置し、昼と夜、または夏と冬（季節）が逆である。意図せずに間違った方のバーミンガム（英語）／バーミングハム（英語）に飛んでしまうと、シャレにならないだろう。

• Some airports also have confusingly similar names, but serve different cities.The code is a useful confirmation that you have a ticket to the correct town, that the travel agent did not mishear Calgary（YYC^IATA）as Cagliari（CAG^IATA）for example. Or you are going to the correct San Salvador or en:Santa Rosa airport and to distinguish airports with the same or similar name, such as which Alexander the Great Airport（KVA^IATA or SKP^IATA)?
• Some airports or cities offer flights to multiple, confusingly-similar destinations. There are two different flights from Toronto to Kingston. One's intraprovincial（YGK^IATA）、the other's going to Jamaica（KIN^IATA).
• To make the confusion complete, tiny en:Nogales is divided by the en:Arizona-en:Sonora border with a different single-runway Nogales International Airport serving en:general aviation on each side of the USA-en:México boundary.

Using the codes can make entering destinations on airline web sites quicker. On check-in, they're useful as a quick visual check that the luggage tag is sending your belongings to where you are travelling, or that the airline has not made a last minute change.

空港名よりも IATA コードで記憶に残る空港は多い

Many airports are known by their code and referenced by local public transport with them and thus the codes can be useful when communicating with taxi drivers. To give just one example, the most convenient bus line to Tegel Airport in en:Berlin is line TXL. They may also appear in diverse contexts as a colloquial nickname for the city which the airport serves.

In general, IATA assigns two-letter codes to airlines and three-letter codes to airports; three-letter codes for non-aviation facilities (such as rail stations with no associated airport) most often begin with Q, X or Z. Codes beginning with Y have for historical reasons mostly been assigned to Canadian airports.

ICAO

ICAO コードは地理的に決まるところが IATA と異なる。

ICAO codes are assigned by the International Civil Aviation Organization, a specialized agency of the United Nations. These four-letter codes are used by aviators for flight plans and navigation; they are separate and different from IATA codes, which are generally used by travel companies for airline timetables, reservations, and baggage tags. For example, the IATA code for London's Heathrow Airport is LHR and its ICAO code is EGLL. ICAO codes are commonly seen by passengers and the general public on flight-tracking services, though passengers will more often see the IATA codes, on their tickets and their luggage tags.

In general IATA codes are usually derived from the name of the airport or the city served, while ICAO codes are distributed by region and country. Far more aerodromes (in the broad sense) have ICAO codes than IATA codes, and to add to the confusion IATA codes (because of their use for ticketing) are sometimes assigned to railway stations. ZYP, for example, is Penn Station in en:New York City.

The first letter of the ICAO code identifies a geographic region, while the second letter usually identifies an individual country or region of a country within that region. en:Canada and the US en:Lower 48 mostly assign ICAO codes which match the same airport's IATA code, by adding a leading 'C' (Canada) or 'K' (USA 48). In other countries, there may be anywhere between a moderate correlation to no correlation between the IATA and ICAO codes.

While IATA codes for any given airport rarely change and sometimes even preserve an anachronistic former name（PEK^IATA for the main airport of en:Beijing for example), ICAO codes may and frequently do change when an airport comes under the control of a different country or government. For example, Berlin Schönefeld Airport remained SXF^IATA but changed its ICAO code upon German reunification as it passed from the GDR to the Federal Republic of Germany.

As IATA is used by travel companies for ticketing and baggage handling, an airport with no scheduled flights may have an ICAO code but no IATA code. There's no corresponding IATA tag for KXTA, the ICAO airport code for en:Area 51 – a closely-guarded military test strip at Groom Lake, Nevada which is not open to civilians.

地域コード

There are other identifiers in use; national rail carriers (such as en:Amtrak) have been known to assign their own non-standard codes to train stations on their own lines and agencies of national governments will assign a location identifier to even the tiniest private landing strip - even if there are no other facilities, no passenger terminal, no tickets and no IATA tags.

In some cases, there's nothing there but a bit of open lake suitable for a float plane; a water aerodrome is open water used regularly to land seaplanes or amphibious aircraft, but typically has no facilities and only a regional location identifier (LID). For instance, "Yellowknife Water Aerodrome" holds a national location identifier (TC LID: CEN9) as Air Tindi Ltd's favourite seasonal spot to land on Great Slave Lake; when a carrier stops using the spot, the identifier is normally revoked.

• In en:Canada, Transport Canada assigns two, three, and four character location identifiers. The TCLID will most often be the same as the IATA code for major passenger airports; a small private airstrip may have just a TCLID. These are not globally unique, but usually avoid overlapping individual FAA LID codes.
• In en:Mexico the Direction General of Civil Aeronautics issues three-letter designators to airports, private airstrips, heliports, boat-heliports and helipads.
• In en:Russia (and, historically, the en:Soviet Union) an internal code (внутренней код) has three Cyrillic letters. These may be used for ticketing and have changed if the name of a city changes.
• In the en:United States of America the Federal Aviation Administration location identifier (FAA LID) is a three- to five-character alphanumeric code identifying aviation related facilities. It will most often be the same as the IATA code for major passenger airports; a small private airstrip will have a string of three or four letters and numbers. A leading 'N' is usually a current or former military base (hence the use of EWR for the civil airport at Newark). Historically, the US National Weather Service also had several schemes for identifying stations (so the 'LA' weather station ID became 'LAX' as an IATA destination), but it now relies on the ICAO and WMO identifiers.

Other identifiers include:

• ITU callsigns for radio stations. These are mostly globally unique as the first few characters identify the country; while mostly used for non-aviation purposes, numbers from this series may identify individual aircraft (for instance, N and a long number on the fuselage of a US plane, CF- and three letters in Canada or F- for a French aircraft).
• World Meteorological Organisation (WMO) identifiers, typically five-digit numeric values, uniquely identify weather stations.
• ICAO has its own standard for weather information, whose predefined message format is the keyword "METAR", followed by the four-letter ICAO location code and the measured data. These re-use the existing ICAO airport identifiers, with one exception: The United States Air Force Weather Agency (AFWA) may assign special-use identifiers beginning with "KQ" to deployed units which lack a permanent code, are mobile or in classified operating locations.
• UN/LOCODE, the United Nations Code for Trade and Transport Locations, assigns five-letter codes to trade and transport locations such as seaports, rail and road terminals, airports, Postal Exchange Office and border crossing points. The first two letters are the country code, so "US NYC" is New York City.

関連項目

• IATAコード全ての一覧は、Wikipedia（英語）をご参照ください。
• en:Metropolitan area airport codes　アメリカの大都市圏の空港コードの記事（英語）。
• en:Airport articles　空港に関する記事（英語）。
• airport listing　都市空港、地方空港を述べた英語版の記事は、カテゴリにまとめてあります。
• 記事で空港コードを記述するテンプレートは、{{IATA}}。
• アメリカの小規模空港のコードは{{tl|FAA LID}}という専用のテンプレートがあります。関連記事は、en:w:FAA LID（英語）。
• 空港を探検するには、記事をご参照ください。en:Wikivoyage:Airport Expedition（英語）