Have you ever thought that maybe, in your dreams of flying, you are really just trying to overcome "real-life" fears? I think that you may be striving for high goals(flying), and then getting scared of taking those leaps, that you then wake up. When people have reoccurring dreams, they usually hint toward something that is happening in their lives, but in odd and peculiar ways.
Although, you should start to take note of when it is, that you wake up. I'm not talking about in the dreams themselves, but what time of day/ night it is when you wake up. In psychology, there have been studies done on dreams. During the portion of your sleep you are in NREM mode, thus meaning that you will not have dreams, or dreams that are remembered when you awake; This is more of a "deep" sleep. When you first fall asleep, you will fall into the REM mode, which is when most of your vivid dreaming will occur. Also at the end of your sleep, when your body is ready to awaken and go on with another new day, you will be in REM mode. This REM mode is a time where you are more likely to awaken during sleep. This also could be the time when you are having such vivid dreams and are awakening; It may not be because you are scared that you awake.