To dream of a passenger represents an aspect of your self that is being carried along with circumstances. It may also reflect secondary factors or problems that are occurring in a situation. Other things that are happening while you are doing something.
To dream of being a passenger may reflect how you are being carried along by a decision or situation. Living with the effects or consequences of a choice. It may also mean that someone else is controlling a situation you are involved in.
Negatively, a passenger may be a sign that you are not in control of a situation. You are letting others decide for you. You may be spending too much energy pleasing others. Alternatively, you may feel that others have been leeching off of you.