We hope to fly in the sky, like two birds, have the wings of the same bird and grow together on the ground, like two branches of a tree. It means: in heaven, I would like to be a bird flying with me. On earth, I would like to grow branches together. It means that people who love each other have deep feelings and share life and death.
"We want to fly in the sky, two birds grow together on the ground with one wing, two branches of a tree." The original book describes the love story of Li Longji, Yang Yuhuan and Yang Guifei, which is very touching. The allusion of "two-winged bird" comes from Shan Hai Jing, which refers to two kinds of birds, one is green and the other is red. These two kinds of birds can't fly without wings, and there is a saying that they are together when they come back from the dead.