A 'passenger novel' is likely a novel centered around the concept of passengers. It may explore different themes related to being a passenger. It could show the diverse backgrounds of passengers and how they cope with the situation of being in transit. It might also delve into the psychological states of passengers, such as their hopes, fears and expectations during the journey.
The 'passenger novel' could potentially revolve around a character who is a passenger in different aspects of life. Maybe it's about a person traveling through various places, facing different situations, and how these experiences shape them. It could also explore themes like loneliness, adventure, or the search for meaning while being on the move.