How to Read a Flight Number: What BA247 or EK001 Actually Means
You've seen them on departure boards, on boarding passes, and on flight tracking apps. But what does a flight number like BA247 or EK001 actually tell you? More than you might think.
The Anatomy of a Flight Number
Every commercial flight has a flight number made up of two parts:
- An airline code — two or three letters (or a letter and a number)
- A numeric identifier — between one and four digits
So BA247 = British Airways, flight 247.
Simple enough — but there's a lot of nuance underneath.
Airline Codes: IATA vs ICAO
There are actually two different code systems used for airlines, and they're used in different contexts:
IATA Codes (2 characters)
These are the codes you see on departure boards, booking websites, and boarding passes. They're issued by the International Air Transport Association.
Examples:
- BA — British Airways
- EK — Emirates
- LH — Lufthansa
- AF — Air France
- QR — Qatar Airways
- AA — American Airlines
- UA — United Airlines
- DL — Delta Air Lines
- FR — Ryanair
- U2 — easyJet
- W6 — Wizz Air
- BY — TUI Airways
- LS — Jet2
- VS — Virgin Atlantic
- SQ — Singapore Airlines
- CX — Cathay Pacific
- JL — Japan Airlines
- NH — All Nippon Airways (ANA)
- QF — Qantas
- AC — Air Canada
- TK — Turkish Airlines
- EY — Etihad Airways
- KL — KLM
- IB — Iberia
- SK — Scandinavian Airlines (SAS)
- AY — Finnair
ICAO Codes (3 characters)
These are used by air traffic controllers and in official aviation contexts. They're always three letters.
Examples:
- BAW — British Airways
- UAE — Emirates
- DLH — Lufthansa
- AFR — Air France
- QTR — Qatar Airways
- AAL — American Airlines
- UAL — United Airlines
- DAL — Delta Air Lines
- RYR — Ryanair
- EZY — easyJet
- WZZ — Wizz Air
- SIA — Singapore Airlines
- CPA — Cathay Pacific
You'll typically see the IATA code on booking systems and departure boards, and the ICAO code (combined with a callsign) used over radio and in ATC systems.
What the Number Tells You
Odd vs Even Numbers
On many airlines, odd flight numbers go in one direction and even numbers go in the other:
- BA117 — London Heathrow to New York JFK (westbound)
- BA118 — New York JFK to London Heathrow (eastbound)
This isn't a universal rule, but it's a common convention, especially on airlines that have operated long-haul routes for many years.
Low Numbers = Prestige Routes
Most major airlines give their lowest numbers to their most important or longest-running routes. BA001 through BA009 are typically premium Heathrow routes. EK001 is Emirates' flagship Dubai to London route. This is largely tradition — there's no technical reason, but it reflects the route's historical importance to the airline.
Codeshare Flights
You might see the same flight operating under two different flight numbers simultaneously. This is a codeshare — an arrangement where two airlines sell seats on the same physical aircraft under their own codes.
For example, a single Lufthansa 747 from Frankfurt to Tokyo might fly as:
- LH710 (sold as a Lufthansa flight)
- NH5710 (sold as an ANA codeshare, under the Star Alliance partnership)
Both codes refer to the same plane, same seats, same flight. On a flight tracking app, it may show the operating carrier (the airline actually flying the aircraft) rather than the marketing carrier.
Ferry Flights
Aircraft often need to be repositioned — flying from one airport to another without passengers. These are called ferry flights or positioning flights. They usually show up on tracking apps with a flight number and no passenger load, sometimes with unusual routings.
Callsigns: What Controllers Actually Say
Pilots and controllers don't use flight numbers directly — they use callsigns. For most airlines, the callsign is the ICAO code plus the flight number.
So BA247 would be called "Speedbird 247" on the radio — because British Airways' radio callsign is "Speedbird" (a nod to the old BOAC logo).
Some famous airline callsigns:
- "Speedbird" — British Airways (BAW)
- "Shamrock" — Aer Lingus (EIN)
- "Clipper" — American Airlines (AAL) — historical, now often just "American"
- "Kangaroo" — Qantas (QFA) — now often just "Qantas"
- "Emirates" — Emirates (UAE)
- "Speedbird" — Also used by some BA subsidiary/franchise ops
- "Monarch" — former Monarch Airlines (now defunct)
- "Jet2" — Jet2 (EXS)
- "Tomson" (phonetic) — TUI Airways
- "Easy" — easyJet (EZY)
- "Ryanair" — Ryanair (RYR)
Low-cost carriers mostly just use their name. Legacy carriers often have historic callsigns from the early days of aviation.
Why Does a Flight Number Sometimes Change Mid-Route?
Occasionally, a flight operates in segments under different numbers. This is common when:
- The aircraft makes an intermediate stop and the passenger mix changes
- A flight number is retired or changed between seasons
- An irregular operation (diversion, delay) requires renumbering
You might also see flights operating under charter codes — for example, a TUI charter might show a different number than a scheduled Jet2 service even if the routes look similar.
Reading Flight Numbers on Tracking Apps
On What Plane?, when you see an aircraft overhead, you'll see its flight number displayed. This tells you immediately:
- Which airline is operating (from the IATA code)
- Roughly where it might be going (if you know the airline's network)
Tap through for full details — route, origin, destination, and more.
Download What Plane? free on the App Store.