A dream analyst will tell you that having a dream about flying symbolizes freedom. People who dream that they are flying always describe it as joyous. It is an implication that you have finally released yourself emotional or physical tension and that you have put all your burdens behind you.
Others believe that flying in a dream is actually one leaving the body during sleep. Spiritual people believe in the notion that we have the ability to leave our bodies into other dimensions and is a practice embraced by many cultures.