--- title: "IATA Codes Explained: Airports, Airlines and Cities" description: "IATA codes for travellers: three-letter airport and city codes, two-character airline codes, why LHR is not LON, and how codeshares reuse marketing codes." url: "https://travelshifu.com/guides/iata-codes-explained/" category: "Glossary" author: "Priya Nair" date_published: "2026-07-21" date_modified: "2026-07-21" source: "TravelShifu" --- # IATA Codes Explained: Airports, Airlines and Cities IATA codes for travellers: three-letter airport and city codes, two-character airline codes, why LHR is not LON, and how codeshares reuse marketing codes. > Educational glossary page. Some links may be affiliate partners at no extra cost to you. ## What are IATA codes? IATA codes are the short identifiers published by the International Air Transport Association — most travellers meet the three-letter airport codes (LHR, JFK, NRT) and two-character airline codes (BA, AA, NH) on tickets and boards. This glossary entry is desk research for July 2026 travellers. Figures and programme names change; treat official portals as the final check. London uses LHR (Heathrow), LGW (Gatwick), STN (Stansted), LTN (Luton) and others; the city code LON appears in some shopping tools as a metro search, not a single runway. Tokyo’s HND and NRT are different ground transfers entirely. ## What is the difference between airport, city and airline codes? Airport codes pin a specific airfield; city codes can cover multiple airports; airline codes brand the carrier — confusing them is how people book the wrong London airport or miss a codeshare operator. London uses LHR (Heathrow), LGW (Gatwick), STN (Stansted), LTN (Luton) and others; the city code LON appears in some shopping tools as a metro search, not a single runway. Tokyo’s HND and NRT are different ground transfers entirely. Airline designators appear as the first two characters of a flight number (BA287, AA100). On codeshares, the marketing airline’s code may differ from the operating carrier that actually flies the metal — baggage rules can follow the operating or ticketing carrier depending on the itinerary. See [codeshare baggage rules](/guides/codeshare-baggage-rules-explained). IATA also maintains location codes used in wider travel tech. Pilots and ops teams may use ICAO’s four-letter codes (EGLL for Heathrow); passengers almost always see IATA’s three letters on boards. ## How do IATA codes show up on a ticket? A ticket reading ‘BA 178 LHR–JFK operated by BA’ is straightforward; ‘AA 6001 LHR–JFK operated by BA’ is a codeshare where American markets a British Airways flight. Always read the operating carrier line before you join the wrong loyalty queue or lounge. Keep your [PNR](/guides/what-is-pnr) handy when apps show only partial code strings. ## IATA codes — related booking terms Codes identify places and carriers; PNRs identify your booking; alliances group carriers for earning and lounge logic. Alliance overview: [airline alliances explained](/guides/airline-alliances-explained). - Is every three-letter code an airport? — Most passenger codes are; some are city or rail codes in special contexts. - Why do some cities share confusion? — Multiple airports under one metro brand. - ICAO vs IATA? — ICAO is four letters for ops; IATA is three for passengers. - Do codes change? — Rarely, but new airports and airline mergers happen. ## How do IATA codes save you from expensive booking mistakes? Verify the three-letter airport code on every booking — city names deceive (Paris has CDG and ORY, London has six airports) — and check the two-letter airline code to know whose metal and rules you are actually buying. Airport codes exist because city names are ambiguous. Booking “Paris” can land you at Charles de Gaulle (CDG) or Orly (ORY), an hour apart; “Washington” splits into Dulles (IAD), Reagan (DCA) and Baltimore (BWI). The classic horror story is the traveller who booked San Jose and meant Costa Rica (SJO) but bought California (SJC). Ten seconds checking the code on the results page prevents a thousand-dollar mistake. The codes also decode your itinerary’s hidden structure. A connection at a different airport in the same city — arriving ORY, departing CDG — is visible only if you read both codes, and it means collecting bags and crossing the city on your own time and money. Airline codes matter too: when the marketing code differs from the operator, you are on a [codeshare](/guides/what-is-codeshare), with all the baggage and service questions that follow. Airports occasionally change codes or names, and new ones open — Istanbul moved from Atatürk (ISL/IST) to the new IST in 2019, stranding travellers with old information. Your boarding pass, bag tag and booking all print the codes; make it a reflex to scan them. Our [travel money guide](/guides/travel-money-guide) primer covers airport strategy, and the [minimum connection time](/guides/what-is-minimum-connection-time) entry explains the legal minimums those codes feed. --- Canonical HTML: https://travelshifu.com/guides/iata-codes-explained/ Last modified: 2026-07-21