Plain English Meaning
It means thinking carefully about who is in the aircraft with you and how they might affect your decisions, your workload, and the safety of the flight.
Full Definition
In the 5P (Plan, Plane, Pilot, Passengers, Programming) risk-management check, 'the Passengers' is the human factor element that requires the pilot to assess how the people on board will affect the safety of the flight. This includes their experience level with flying, their physical condition, their expectations, any pressure they may place on the pilot to complete the flight, and their potential to distract or assist during normal and abnormal operations.
Context Anchor
Used during single-pilot risk management and the 5P Check before and during a flight.
Derivation
Passenger comes from passage, meaning a journey from one place to another. A passenger is someone making that journey while being carried by the aircraft, which helps separate the idea from , , or equipment.