Abstract: An airport communication system (1) has a tag (10) affixed by a clip (12) to each passenger en route between check-in and boarding. Each tag (10) transmits an identifier on a particular RF channel with a short range, and the location of a transponder (5) which received the transmission indicates passenger location. A server (4) correlates tag and passenger identifiers and generates alerts if alert conditions are met such as excessive distance from a boarding gate at a particular time.