to avoid the situation where the suction jet pump is kept in operation when the liquid trap is empty according to various embodiments switching off the suction jet pump when the liquid trap is empty prevents an unnecessary energy consumption and an unnecessary formation of foam in the fuel container as a rule it is sufficient to carry out the sucking away of the fuel from the liquid trap only when a filling level provided is reached in this case the ventilation device according to an embodiment has a particularly simple structural configuration when a filling level limit switch for switching the valve is arranged in the liquid trap according to another embodiment the filling level limit switch has a particularly simple structural configuration when the filling level limit switch has a float the control of the valve could for example take place completely mechanically in that a valve body movable against a valve seat is connected to the float however according to another embodiment the suction jet pump can be activated particularly reliably when the valve is switched electrically the valve can be manufactured particularly cost effectively when the valve has an electric actuator and a valve body movable against a valve seat is connected to the actuator the electrically switched valve has a particularly simple structural configuration when the electric actuator has an electromagnet or a piezo element according to another embodiment the control of the electrically switched valve is particularly.