Your flight reservation number, often called a Record Locator or PNR (Passenger Name Record), is a unique 6-character alphanumeric code (e.g., ABCD12). You can primarily find it in your confirmation email sent by the airline or travel agency immediately after booking, usually located in the header or "Flight Details" section. It is also clearly printed on your boarding pass (physical or digital) and can be accessed by logging into the "Manage Trips" section of the airline’s official website or mobile app using your last name. If you booked through a third party like Expedia or Kayak, you may see two numbers: one for the agency and one specifically for the airline; you need the airline’s code to check in or select seats. If you cannot find either, your 13-digit ticket number (starting with the airline's 3-digit code) is a viable alternative for locating your trip.