Record locators are unique within a given CRS at a specific point in time. Because the number of character combinations in characters is finite, albeit very large, record locators may be reused once the PNRs to which they refer have been purged from the CRS.

Yes, airlines do reuse record locators (also known as PNRs or confirmation numbers), but they follow a strict "cooling off" period to prevent confusion. A record locator is a six-character alphanumeric string (e.g., AB12CD), and because there are a finite number of combinations (approx. 2.1 billion), airlines must eventually recycle them. In 2026, most major carriers wait at least 6 to 12 months after a journey is completed or a ticket is cancelled before putting that specific code back into the pool. This is why you might occasionally see an "Error" or "Old Trip" if you try to search for a code from several years ago. It is a high-value peer tip to keep your e-ticket number (the 13-digit code starting with the airline's 3-digit code) as a permanent backup, as e-ticket numbers are unique to you and your specific transaction and are never reused, providing a more reliable way to track your travel history or file a claim long after the record locator has been assigned to someone else.