The answer is personal and spiritual exploration because romantic literature was meant to make the mind wander into romantic stories of love and romance where one found out more about themselves while falling in love. At least, that is my best guess since it's certainly not supposed to be rational and well reasoned ideas, it's not about religion, and I don't think it's supposed to empasise on society.
In Mattie's mind, Blanchard's balloon—“a yellow silk bubble escaping the earth”—symbolizes freedom, particularly an escape from her home, where she feels as if she's trapped and treated like a child.
