Educational glossary entry for July 2026 planners. Not legal, immigration, medical or financial advice. Confirm official sources for your nationality, route and booking. <!-- VERIFY -->
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.
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.
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 handy when apps show only partial code strings.