during your waking life, go swimming, go on swings and jump off, and practice gymnastics or extreme rollerblading where you are jumping onto/off of things. Also, when you get to the top of stairs, try to jump over them and all the way to the bottom. Go on some upside down rollercoasters too. I have done these things many times in my life. Also, jump off high things in your dreams. Pretend you are swimming in the air. These are some things to help you fly in dreams if you don't know how.