What term is used for a passenger who presents for check-in but does not board the aircraft?

The term used for a passenger who presents for check-in but does not board the aircraft is commonly referred to as a "Left Behind Passenger." This designation highlights the situation where the individual has completed the necessary check-in process and arrived at the airport but ultimately does not make it onto the flight for various reasons, such as time constraints, accidental delays, or personal decisions. This term is significant in the aviation industry, as it allows airlines to track and understand passenger behavior and improve their operational procedures related to boarding and check-in processes.

The other options describe different scenarios. "Inadmissible Passenger" refers to someone who, upon arriving at a destination, is not allowed to enter a country due to immigration or legal issues. "Maas Passenger" isn’t a widely recognized term in the aviation context and seems to be a typographical error or misinformation. "Misconnection" pertains to a passenger missing their connecting flight because their previous flight was delayed or they arrived late, which is distinct from the scenario of not boarding after check-in. Understanding these distinctions helps ensure clarity in communication within aviation operations.