This dream may represent some aspect of your personality or feelings that are soaring and free. Alternatively, it could symbolize a time when you feel like you're in the air, experiencing something new and exciting.
This dream could represent an interest or hobby that you're passionate about. Alternatively, it could be a sign that you feel like you're on top of the world - in control and able to do whatever you want.
This is my interpretation of what it means to dream of a bird in flight. At times, the best interpreter of a dream is the person who had the dream. Always keep your own life and nuances in mind when trying to determine what you think a dream might mean, or if it meant anything at all.