Airline codes decoded: designators, ICAO codes and flight numbers

Airline codes are short identifiers that let booking systems, airports and air traffic control refer to an airline without spelling out its name. Most scheduled airlines have three:

• a two-character IATA designator, which you see in flight numbers, on tickets and on departure boards;
• a three-letter ICAO designator, used in flight plans and air traffic control;
• a three-digit accounting code, which forms the start of every ticket number the airline issues.

Look up any airline by name or code in our airline code finder.

The three codes side by side

	IATA designator	ICAO designator	Ticket (accounting) code
Format	2 characters, letters or a letter and a digit	3 letters	3 digits
Emirates	EK	UAE	176
Qatar Airways	QR	QTR	157
American Airlines	AA	AAL	001
Where you see it	Flight numbers, bookings, bag tags, boards	Flight plans, flight-tracking sites	First three digits of the ticket number
Issued by	IATA (airline trade association)	ICAO (UN aviation agency), on request of the airline’s State	IATA

IATA designators: the code in your flight number

The two-character designator is the airline part of every flight number: in a flight numbered PK 123, PK is Pakistan International Airlines. (Flight numbers on this page are illustrative.) IATA assigns designators to airlines holding a government air operator certificate.

Designators can contain a digit. IndiGo is 6E and Air Arabia is G9. That’s one reason not to assume a code is two letters when typing it into a search box.

Two carriers can occasionally share a designator. IATA marks these “controlled duplicates” with an asterisk in its directory; they’re issued to non-scheduled operators, which can’t use them to publish schedules. For booking purposes, a designator points to one airline.

ICAO designators: the code air traffic control uses

ICAO’s three-letter designators identify an aircraft operator in flight plans, and come with a telephony designator, the word pilots and controllers say on the radio before the flight number. ICAO publishes them in Designators for Aircraft Operating Agencies (Doc 8585), updated four times a year, and registers them only at the request of the airline’s home State. ICAO itself warns not to confuse them with IATA’s two-letter reservation codes.

ICAO and IATA codes often look unrelated:

Airline	IATA	ICAO
British Airways	BA	BAW
Lufthansa	LH	DLH
Pakistan International Airlines	PK	PIA
flydubai	FZ	FDB
IndiGo	6E	IGO

You’ll meet ICAO codes on flight-tracking websites, which often show a flight as UAE123 rather than EK 123. It’s the same flight under its ICAO code.

The three-digit ticket code

Each airline that issues tickets also has a three-digit passenger accounting code. It becomes the first three digits of every 13-digit ticket number it issues: 176 for Emirates, 157 for Qatar Airways, 001 for American. Our e-ticket number guide explains the rest of the number and where to find it.

How codes appear in a flight number

A flight number is the airline designator followed by a number, usually of one to four digits, such as BA 12 or PK 123. A few things to know:

• The same physical flight can carry several flight numbers when partner airlines sell seats on it (codesharing). The “operated by” line tells you which airline is flying; our guide to reading a flight itinerary shows where it appears.
• Airlines sometimes change flight numbers with a new schedule, so check the number on your latest itinerary.
• The airline code in a flight number is never an airport code. EK is Emirates; DXB is Dubai’s airport. Our guide to airport codes explains those.

Questions people ask

What’s the difference between IATA and ICAO airline codes?

IATA’s two-character codes are for commercial use: bookings, tickets and timetables. ICAO’s three-letter codes are for operations: flight plans and air traffic control. Most scheduled airlines have both.

Can an airline change its code?

It can happen, for example after a merger or when a new airline takes over operations. Always use the code shown on your current booking.

Why do some airline codes include numbers?

IATA designators are two characters, and those characters can be letters or digits. 6E (IndiGo) and G9 (Air Arabia) are examples.