How are flight numbers assigned?

🕗 3 minutes | July 2, 2024 | Text Kamil Wrzosek (opens in a new tab)

LO45, LO331, LO3836 – What Do These Flight Numbers Mean? You've probably seen flight numbers on your boarding pass, at the gate, on a flight radar, flight information board, flight maps, or even as part of your booking reference. But have you ever wondered how flight numbers are assigned and what they mean? If so, keep reading, and we’ll clear up the mystery!

A flight number is a combination of letters and numbers that represents a specific route operated by an airline. Let’s start with the letters. These refer to the airline’s individual code, assigned by IATA (International Air Transport Association). For LOT Polish Airlines, the LO prefix is used.

Numbers, however, follow general guidelines, though each airline has its own rules for assigning them. Flight numbers can range from 1 to 9999.

Most airlines follow a common convention:

• Odd numbers are usually assigned to outbound flights.
• Even numbers are typically assigned to return flights.
• Charter flights operated by LOT have four-digit flight numbers starting with 6.

Example:

• Warsaw – Toronto → LO45
• Toronto – Warsaw → LO46

You may have noticed that some flight numbers have two, three, or four digits. What does this mean? The lower the flight number, the more significant the route for the airline.

• Long-haul, intercontinental routes: Two-digit flight numbers.
• International short-haul flights: Three-digit flight numbers.
• Domestic and charter flights: Four-digit flight numbers.

Now, when looking at a flight schedule, you’ll be able to quickly identify the type of route!

If you're travelling to a destination served by multiple airlines, your flight number displayed at the gate ensures that you’re boarding the correct aircraft. This helps manage airport operations efficiently and prevents mistakes.

Flight numbers also play a crucial role when checking a flight's status, current location, or potential delays.

With publicly available tools like Flightradar24, you can:

• Identify a specific aircraft.
• Track its real-time location.
• Check departure and arrival details.

This is useful for monitoring your own flight or keeping track of a loved one's journey.

Flight numbers aren’t just important for passengers and airlines—they are critical for air traffic controllers (ATC).

ATC uses flight numbers to:

• Identify and track commercial, military, private, and emergency flights.
• Manage landing and takeoff sequences.
• Prioritize air traffic operations.

Each aircraft’s flight number and transponder data allow controllers to see:

• Flight status
• Aircraft position
• Speed and altitude
• Type of flight (commercial, private, cargo, etc.)

This ensures smooth and safe air traffic management.

Through codeshare agreements, you can book flights operated by other airlines under the flight number of the airline you purchased your ticket from.