It requires constant awareness(willpower) to keep that lucidity and focus, or the dream mutates to whatever you focus on and you're back in normal dreamland. An

It requires constant awareness(willpower) to keep that lucidity and focus, or the dream mutates to whatever you focus on and you're back in normal dreamland. Any physical activity there costs willpower, so you're not flying all the time(unlike VR where your activity can be a passive state(observer),in dreams all states are active processes and observing changes the dream itself(its much harder to be a neutral observer)).