Dreams in which one can fly falls into the category of "dreams of enlightenment". These dreams occur when you realize that you are dreaming. Many people describe the ability to fly in their dreams as refreshing and a fun experience.
If you fly with ease and enjoy the scenery and landscape below you, it implies that you are on top of any situation. Flying over a building could also mean that you start looking at things differently. Dreams of flight and the ability to control the flight show your personal sense of power.
If you have difficulties to keep flying, it shows a lack of power in controlling your own situation. You can fight to stay in the air to keep the course. Things like power lines, trees, mountains, may prevent you to further your flight. These obstacles symbolize specific difficulties or people who stand in your way in reality. You must determine who or what prevents you to move forward. It may also be an indication of lack of confidence. One must believe in themselves and not be afraid!
If you feel fear when you fly or you think that you fly too high, it implies that you are afraid of challenges and success.
Of course, in real life we can not fly. Therefore, these dreams may represent that of which is beyond our physical capabilities. In your mind, you can be anyone and do anything. Another way to interpret these dreams is that they symbolize strength and your will. Feeling invincible, and nobody can tell you that you are not able to do or accomplish something. Undoubtedly these dreams leave a fabulous sense of freedom.