What's in a Dream?

Last weekend our national TV station here in Finland broadcasted Arizona Dream, a movie by Emir Kusturica. I'd seen it before but it remains a powerful movie and it made me thinking about the two totally different meanings of dream. The movie actually clearly plays on both meanings.
First, and foremost, we humans (but apparently quite many animals too), have, or rather "see", dreams, in our sleep. Those dreams can be difficult to describe, although many experience vivid details. There isn't always a clear "plot"; and the setting or situation may feel surreal; like that movie. It seems that most of our dreams are about more or less frightening situations; that's definitely true for myself. Antti Revonsuo proposed an interesting evolutionary psychology based theory for dreams: in our dreams our brains prepare themselves for dealing with dangerous situations.
The other meaning is to have a dream, as in having a vision or goal. An epitome of this meaning is the concept of the American Dream. In the movie several characters express their dreams of this kind. I realized that in Finnish there is actually a different verb for having-a-dream of this kind (wish, goal): unelmoida.
In the movie Elaine dreams of being able to fly. Interestingly Elaine not only talks about having the wish to fly but also about seeing dreams in which she simply steps of a roof and flies away. Revonsuo's theory now inspires me to engage into some speculation. In many dangerous situations , that our dreams simulate, a pretty effective tactic is to flee. And flying is, or would be, the ultimate way to flee. So perhaps dreams induce in us humans the strong wish to fly. Perhaps this also explains the great excitement and satisfaction that free-flyers (hang- and paragliding pilots) experience; they almost fly like birds, just stepping of a mountain or cliff.