A flight reservation code, commonly known as a PNR (Passenger Name Record) or a Record Locator, is a unique six-character alphanumeric code (e.g., AB12CD) that serves as the "key" to your booking in an airline's database. This code links your name to your specific itinerary, seat selection, meal preferences, and payment details. It is important to distinguish between the Booking Reference provided by a travel agent (which identifies the sale) and the Airline Confirmation Code (the PNR), which is what you actually need to check in online or at a kiosk. If your trip involves multiple airlines, you may actually have different PNRs for each carrier, even if they are on the same "itinerary." Keeping this code private is vital for security; with just your last name and your PNR, someone could potentially access your personal data or even cancel your flight. You can usually find it in the top right corner of your e-ticket or in the confirmation email sent immediately after purchase.