I am going to add that even if the air is rarified, if you are travelling with enough speed, a very high speed, the vehicle will still pass through enough volume of air every second to provide both lift and control authority.
Lets go to another vehicular body here, that was just shown, the DF-17. There is still a bit of lifting body that demonstrates that even at the altitudes it fly, there is enough air that is passing underneath it to exert some lift authority on the body, and the presence of stabilizers, also show there is still enough air pressure as a result of the speed, that fin stabilizers are still valid.
With both bodies, the WZ-8 and the DF-17, they have a light nose, with the center of gravity of the vehicle towards the back. That and with the nose getting the highest pressure, the nose will have a tendency to pitch and lift up, increasing the angle of attack. But as it does, it will also increase drag, so the vehicle will have to pitch down periodically, the slight dive will decrease altitude but pick up and restore speed. The increase speed will increase lift again and the nose will pitch up, increasing altitude but decrease speed. Then you pitch down again, and this cycle repeats itself. The vehicles will not be traveling in a straight line but in a wave like motion.