There are many interpretations of dreaming about flying in psychology, and one of them fits Xiao Qian's current situation perfectly.
It is about unfulfilled desires. She was all ready to park the car and do "that" with him in Maple Forest at night, but then her period arrived like blooming flowers in February. Don't think that only men would suffer nosebleeds; women would feel even worse when their desires were unfulfilled, and their inner fire couldn't be extinguished. The frustration built up to the point that it manifested in her dreams, where she could fly freely...
Yu Minglang was very intelligent. He would definitely understand the meaning of this dream, and Xiao Qian felt a little proud thinking about his possible reaction.
That's the taste of love, teasing each other in circles, both the teaser and the one being teased feel happy.