Airline codes explained

Airlines carry three separate identifiers, and a flight number that combines one of them with a number. Each serves a different audience.

IATA vs ICAO airline codes: the difference

	IATA airline code	ICAO airline code
Length	2 characters, letters or a letter and a digit	3 letters
Example	BA British Airways · EK Emirates	BAW British Airways · UAE Emirates
Used for	Flight numbers, bookings, tickets, baggage tags	Air traffic control, flight plans, radio callsigns
Seen by passengers?	Yes — on every itinerary and boarding pass	Rarely — mostly on flight-tracking sites
Reassigned?	Yes, after an airline stops flying	Far less readily

In one line: IATA codes are the commercial codes passengers see; ICAO codes are the operational codes pilots and controllers use. The sections below take each in turn, then the full list for 30 major airlines.

IATA designator: two characters

BA, EK, AA, 6E. This is the code you see in flight numbers and on itineraries. It can include a digit — 6E is IndiGo, 9W was Jet Airways — because two letters ran out.

IATA designators are reused. When an airline ceases operations its code is eventually reassigned, which is why historical timetables can be misleading.

ICAO designator: three letters

BAW, UAE, AAL, IGO. Used in air traffic control and flight plans, and never reassigned in the same casual way. ICAO also assigns each airline a radio callsign — BAW is spoken as “Speedbird”, UAE as “Emirates”, DLH as “Lufthansa” — which is what you hear on air traffic control recordings.

Numeric accounting code: three digits

125, 176, 001. Used for ticketing and interline settlement, and forming the first three digits of every e-ticket number issued on that airline’s stock.

The three side by side

Airline	IATA	ICAO	Ticket prefix	Callsign
British Airways	BA	BAW	125	Speedbird
Emirates	EK	UAE	176	Emirates
American Airlines	AA	AAL	001	American
Lufthansa	LH	DLH	220	Lufthansa
Singapore Airlines	SQ	SIA	618	Singapore
Qatar Airways	QR	QTR	157	Qatari

Airline codes list: 30 major carriers

Every airline in this site’s directory, sorted by IATA code. Each name links to the airline’s page, with its hubs, alliance partners and a prefilled itinerary builder.

The airline code lookup searches the same set by code or name.

Flight numbers

A flight number is the IATA designator plus one to four digits: BA112, EK1, SQ22.

The numbering is not random, though conventions vary by airline:

• Lower numbers often mark flagship routes. SQ21/SQ22 is Singapore–Newark. EK1/EK2 is Dubai–London Heathrow.
• Direction is usually encoded in parity. Many airlines use even numbers eastbound or northbound and odd numbers westbound or southbound.
• Number blocks group by region or subsidiary. A four-digit number in the 3000s or above is very often a regional affiliate or a codeshare.
• Numbers are retired after major accidents, which is why certain gaps exist.

Flight numbers change between seasons. A number is not a permanent identifier for a route.

Marketing carrier vs operating carrier

The distinction that causes the most airport confusion.

Marketing carrier — the airline that sold you the ticket and whose code is in the flight number.

Operating carrier — the airline that actually operates the aircraft, employs the crew, and whose desk you check in at.

On a codeshare, one flight is sold under several flight numbers by several airlines. A single departure might be BA1234, AA5678 and IB9012 simultaneously. One aircraft, three flight numbers, three sets of passengers who each believe they are flying a different airline.

Your itinerary is required to disclose this. Look for “operated by”.

Why it matters practically:

• Check-in is with the operating carrier, at their desk, in their terminal.
• Baggage rules are usually the operating carrier’s, and can differ from what the marketing carrier’s website advertised.
• Seat selection frequently has to be done on the operating carrier’s site, sometimes with a different booking reference.
• Delay and cancellation handling is the operating carrier’s, though your contract is with the marketing carrier.
• Frequent-flyer accrual depends on the fare class and the alliance relationship, not on whose name is on the ticket.

Alliances

Three global alliances group carriers for reciprocal benefits:

• Star Alliance — Lufthansa, United, Singapore Airlines, Air Canada, Turkish Airlines, ANA, Thai Airways, Swiss, Austrian, Air India, EVA Air
• Oneworld — British Airways, American Airlines, Qatar Airways, Cathay Pacific, Qantas, Iberia, Japan Airlines, Finnair, Malaysia Airlines
• SkyTeam — Delta, Air France, KLM, Korean Air, Saudia, Virgin Atlantic, SAS

Emirates, Etihad and most low-cost carriers sit outside the alliance system, using bilateral partnerships instead. The airline directory shows membership for each carrier.

Alliance membership affects lounge access, mileage earning and through-checking of baggage. It does not by itself mean two airlines will look after you if a self-transfer goes wrong — that depends on whether the journey is on one ticket.

On a sample itinerary

Airline codes are public reference data, so a sample can show a real carrier code and a plausible flight number as an illustration of a routing. What it cannot do is imply that a specific flight was booked on that carrier. That claim would live in the booking reference — which stays blank.

Related reading

• Airport codes explained
• E-ticket number explained
• Every field on a flight itinerary explained