I think this is generally a natural issue. I find the best way to combat it is to focus on things other than that you're flying. Feel the wind rush against you, watch the world pass by and stay focused on your senses, how the cool air feels, how it smells, how everything looks from your in-air vantage point. Also be aware of where all your limbs are in space, it's surprising how easy it is to lose track of that.

I don't think you could ever have the same mind-blowing realism in a dream while flying that you can while on flat ground, but doing these things can help.