Which type of passenger is defined by arriving at least 6 hours before their flight?

The definition of a passenger who arrives at least 6 hours before their flight aligns with the concept of a "Wash-up Passenger." This term refers to individuals who arrive at the airport well in advance to allow themselves enough time for security screening, check-in, and any unforeseen delays or complications. Such passengers often prefer to arrive early for a variety of reasons, including relaxation, avoiding last-minute stress, or taking advantage of airport amenities.

In contrast, the other types of passengers have different characteristics based on their travel patterns. A Stay-In Passenger typically refers to someone who remains at the airport terminal or surrounding area for an extended period, often implying a longer duration than just the early arrival before a flight. A Layover Passenger is one who has a scheduled stop between flights but does not necessarily have a waiting time exceeding 6 hours. A Transit Passenger refers to those who are passing through the airport temporarily on their way to another destination, which may also not involve a lengthy wait.

Thus, the definition that specifically identifies a passenger arriving 6 hours in advance is uniquely descriptive of the Wash-up Passenger.