I think it starts as unrequited love, the guy longs to be with her but she teases him and escapes everytime. And at the end when the guy gave her everything he has (notice how the drawing of the guy loses details) and she decides to be with him, he no longer sees her as being special and walks away. I don't know!!
Or it could be two people in love and having the same dream of being together, but wake up to reality.
Or it could be about freedom, the guy longs to possess her but she flies away, and at the end realizes that she misses him too...but things fall apart because he is tired of waiting. :( How would you interpret this?