This dream may represent feelings of being trapped and controlled in your waking life. The age range of 4 to 11 suggests that these feelings may have originated in childhood and have continued to haunt you. The people chained to seats, including yourself, symbolize a lack of freedom and autonomy. The moving car could represent the journey of life and the feeling of being unable to control its direction. The people in uniforms and gas masks may represent authority figures or societal pressures that you feel are oppressive and intimidating. The gas filling the room could symbolize a suffocating and overwhelming sense of fear and powerlessness. The reference to events in Germany during WW1 and WW2 may suggest a connection to historical or ancestral trauma. This dream may be a manifestation of repressed emotions and a reminder to confront and overcome these feelings of oppression and fear in your waking life.