Yes, in almost all practical travel contexts, a PNR (Passenger Name Record) is the same thing as an airline reference number, booking code, or locator. A PNR is a unique six-character alphanumeric code (e.g., XL92B4) generated by a Computer Reservations System (CRS) that contains all the high-fidelity data about a traveler's itinerary. This includes flight details, passenger names, contact info, and special requests like meal preferences or wheelchair assistance. However, there is a high-fidelity technical nuance to be aware of in 2026: if you book through a third-party site like Expedia or a partner airline, you might actually have two different codes. One is the Global Distribution System (GDS) locator used by the travel agent, and the other is the "Airline Record Locator" used by the carrier actually operating the plane. To check in online or manage your seat selection, you must ensure you are using the specific high-fidelity airline reference number recognized by the airline's own internal system, rather than just the agency's internal booking ID.