Flight number

In the world of flying, a flight number is a special code that helps us know which airplane trip we are talking about. It is made up of two letters and one to four numbers. The two letters stand for the airline, like QF for Qantas Airways. The numbers tell us which specific trip it is. For example, QF9 is a flight from Perth, Australia, to London Heathrow.

A flight can be called "direct" even if it stops along the way, as long as it uses the same flight number the whole journey. For instance, QF1 goes from Sydney to Singapore to London on Qantas Airways.

Sometimes, different airlines can share the same flight path under a code-sharing agreement. This means a part of the trip might have a different flight number for another airline. The flight number we usually hear about includes both the airline letters and the numbers, even though strictly speaking, the number alone is the flight number.

The flight number of the airline that actually operates the flight is also used as a special radio name, called a call sign. This is different from the aircraft's registration number, which tells us the unique name of the airplane itself.

Conventions

Airlines use special numbers to identify their flights. These numbers help us know which flight is which. For example, flights going east or north often have even numbers, while flights going west or south have odd numbers. Sometimes, the same route might have a pair of numbers like 401 for one direction and 402 for the return trip.

Airlines also have special rules for different types of flights. Very short numbers, like 1, are often used for important or long-distance flights. Numbers between 3000 and 5999 might be used for smaller regional flights, and numbers above 6000 can be for flights operated by different airlines or even train services.

In China, flight numbers have their own unique system. Before 1988, the first digit showed where the flight started, and the last digit showed if it was going out or coming back. Today, airlines in China have specific number ranges, but these rules are not always followed strictly anymore.

Codeshare

Main article: Codeshare agreement

In a codeshare, airlines work together by sharing their planes. This means one flight can have more than one flight number, even if it’s on the same route. For example, a flight like QF8412 goes from Dubai to Sydney, but it might also be called EK412 because another airline is sharing it. Similarly, a flight like QF3920 from Lima, Peru to Santiago, Chile might also be listed as LATAM 523.

List of Lowest-Numbered Passenger Flights by Airlines

Most flights go straight from one place to another, but some have stops along the way. Sometimes the plane might change types because of needs or unexpected situations.

A famous flight number 1 used to be British Airways flight BA1, which flew using the Concorde between London Heathrow and New York's John F. Kennedy airport. After the Concorde stopped flying in 2003, the flight number was used again in 2009 for an all business class A318 flight from London City Airport to New York JFK, stopping in Shannon, Ireland. This route stopped in 2020 because of the COVID-19 pandemic, and British Airways said it would not start again.

Airline	IATA Flight No	ICAO Flight No	From	To	Then to (if applicable)	Aircraft Type
Aeroméxico	AM1	AMX1	Mexico City	Madrid		Boeing 787-8/787-9
Air Canada	AC1	ACA1	Toronto–Pearson	Tokyo–Haneda		Boeing 777-300ER
Air Canada Express	QK1	JZA1	Montreal	Ottawa		Bombardier CRJ900
Air China	CA101	CCA101	Beijing-Capital	Hong Kong		Comac C919
Air France	AF1	AFR1	New York–JFK	Paris–CDG		Boeing 777-200ER / 777-300ER
Air Japan	NQ1	AJX1	Tokyo–Narita	Bangkok–Suvarnabhumi		Boeing 787-8
Air Macau	NX1	AMU1	Beijing–Capital	Macau		Airbus A321
Air New Zealand	NZ1	ANZ1	New York–JFK	Auckland		Boeing 787-9
Air Niugini	PX1	ANG1	Port Moresby	Sydney		Boeing 737-800
Air Tahiti Nui	TN1	THT1	Los Angeles	Papeete		Boeing 787-9
Alaska Airlines	AS1	ASA1	Washington–Reagan	Seattle		Boeing 737-800
American Airlines	AA1	AAL1	New York–JFK	Los Angeles		Airbus A321
Cape Air	9K1	KAP1		Martha's Vineyard	Nantucket	Cessna 402
Delta Air Lines	DL1	DAL1		London–Heathrow		Boeing 767-400ER
El Al	LY1	ELY1	Tel Aviv	New York–JFK		Boeing 787-9
Emirates	EK1	UAE1	Dubai	London–Heathrow		Airbus A380-800
Etihad Airways	EY1	ETD1	Abu Dhabi	New York–JFK		Airbus A380-800 / Boeing 787-9
FedEx Express	FX1	FDX1	London–Stansted	Memphis		Boeing 777F
Finnair	AY1	FIN1	Helsinki	Los Angeles		Airbus A350-900
Flydubai	FZ1	FDB1	Dubai	Doha		Boeing 737-MAX 8
Hawaiian Airlines	HA1	HAL1	Los Angeles	Honolulu		Airbus A330-200
Japan Airlines	JL1	JAL1	San Francisco	Tokyo–Haneda		Boeing 777-300ER
Japan Transocean Air	NU1	JTA1	Osaka−Kansai	Okinawa−Naha		Boeing 737-800
JetBlue Airways	B61	JBU1	New York–JFK	Fort Lauderdale		Airbus A321-200 / Airbus A320-200
Jetstar	JQ1	JST1	Melbourne	Honolulu		Boeing 787-8
Jin Air	LJ1	JNA1	Seoul–Incheon	Bangkok–Suvarnabhumi		Boeing 737-800
LATAM Chile	LA1	LAN1	Santiago	Puerto Natales		Airbus A320
LOT Polish Airlines	LO1	LOT1	Warsaw	Chicago–O'Hare		Boeing 787-8
Lufthansa	LH1	DLH1	Hamburg	Frankfurt		Airbus A321 / A320neo
Malaysia Airlines	MH1	MAS1	London–Heathrow	Kuala Lumpur		Airbus A350-900
Nauru Airlines	ON1	RON1	Nauru	Brisbane		Boeing 737-300
Qantas	QF1	QFA1	Sydney	Singapore	London–Heathrow	Airbus A380-800
Qatar Airways	QR1	QTR1	Doha	London–Heathrow		Boeing 777-200LR / 777-300ER / Airbus A350-900
Royal Brunei Airlines	BI1	RBA1	Bandar Seri Begawan	Jeddah		Boeing 787-8
Scandinavian Airlines	SK1	SAS1	Lulea	Stockholm		Airbus A320neo
Skymark Airlines	BC1	SKY1	Tokyo–Haneda	Fukuoka		Boeing 737-800
Southwest Airlines	WN1	SWA1	Dallas–Love Field	Houston–Hobby	Corpus Christi	Boeing 737-700 / 737-800 / 737-MAX 8
SpiceJet	SG1	SEJ1	Chennai	Colombo		Boeing 737-800
Spirit Airlines	NK1	NKS1	Fort Lauderdale	Chicago–O'Hare		Airbus A321 / Airbus A321neo
Spring Japan	IJ1	SJO1	Tokyo-Narita	Shanghai-Pudong		Boeing 737-800
Starlux Airlines	JX1	SJX1	Los Angeles	Taipei–Taoyuan		Airbus A350-900
Turkish Airlines	TK1	THY1	Istanbul	New York–JFK		Boeing 777-300ER
United Airlines	UA1	UAL1	San Francisco	Singapore		Boeing 787-9
WestJet	WS1	WJA1	London–Heathrow	Calgary		Boeing 787-9
Zipair Tokyo	ZG1	TZP1	Honolulu	Tokyo–Narita		Boeing 787-8

Flight number changes

Airlines sometimes change flight numbers after serious problems happen. For example, after some flights had trouble, the airlines changed their numbers. This helps avoid reminders of past incidents.

Sometimes, when airlines change their routes, they also change the flight numbers to match the new paths.

Flight number conservation

When big airlines merge, they sometimes need to use the same flight numbers for different routes. Groups like IATA and ICAO, along with systems used for booking tickets and air traffic control, only allow flight numbers up to four digits (from 0001 to 9999). Because there are so many flights now, some airlines use one flight number for trips in both directions, like going from DCA to PBI and then back to DCA. Other times, one flight number might cover a trip with many stops, such as going from ICT to DAL, then HOU, MDW, OMA, DEN, ABQ, LAS, and finally BDL.

Flight designator

In aviation, a flight designator is a special code used for airline flights. It has two letters that tell us the airline, followed by 1 to 4 numbers. For example, QF9 is a flight by Qantas Airways from Perth, Australia to London Heathrow. When a flight uses one designator for the whole trip, even with stops or plane changes, it is called a "direct" service.

Main article: Standard Schedules Information Manual
Main articles: International Air Transport Association

Spacecraft

Flight numbers are sometimes used for spacecraft, too. For example, rockets that can only be used once might have a flight number that is more like a serial number. The Space Shuttle missions used numbers that started with "STS", like STS-93. SpaceX gives numbers to each flight of the same booster. For instance, Crew-2 used booster B1061.2, which was the second time that booster B1061 flew.