The flight number is a specific alphanumeric code assigned to a particular flight route on a specific day. It usually consists of a two-letter airline designator (the IATA code, like "AA" for American Airlines or "BA" for British Airways) followed by a one- to four-digit number (e.g., AA123). This number is used by Air Traffic Control, airport staff, and passengers to identify the flight throughout the aviation system. It is different from your confirmation number (or PNR), which is unique to your personal reservation. You can find the flight number prominently displayed on your boarding pass, your e-ticket confirmation email, and the airport departure screens. Knowing your flight number is essential for tracking the aircraft's status, finding the correct check-in counter, and identifying the right baggage carousel upon arrival. It essentially acts as the "name" of the service you are traveling on, distinguishing it from other flights departing at similar times.