This is just something I've been thinking about. I have no idea if it has any validity.
We sometimes hear that, when dreaming, our "astral body" leaves the physical body and explores a nonphysical plane. Our dreams are said to be garbled recollections of this exploratory activity.
In this respect, it's interesting to look at some of the most common dreams. For instance, many people have dreams in which they are flying through the air. This type of travel is consistent, at least, with an out-of-body experience; OBErs often say that they float weightlessly, or flash from one location to another at the speed of thought.
For my part, I've often had dreams that involve a sort of levitation. Sometimes I dream that by concentrating very hard, I'm able to lift myself off the ground and float up to the ceiling. Amusingly, I tend to bob up and down, lightly bouncing off the ceiling, while exploring the room from that vantage point. I often find myself impressed at how easy it is to do this, and I wonder why it ever seemed difficult.
In other dreams, I've imagined myself floating down the street, surrounded by other people who are similarly levitating. In one vivid dream, I effortlessly rose up over the trees, and was then able to step from treetop to treetop, kind of bouncing along in languid slow-motion.
The most obviously OBE-like dream I've had involved my rising up out of my sleeping body and then floating up the stairs to the second level of my home. Was it a true OBE, or only a dream? I don't know, but it was certainly vivid.
I find that I often have dreams involving travel by plane, train, or auto. The airplane dreams are especially interesting, in that the plane (usually a big jetliner) is flying low to the ground, swooping over telephone poles and trees. There is no sense of danger. Again, this could possibly suggest a memory of some unusual form of movement. The idea of travel, in and of itself, is consistent with moving from one plane of reality to another. Some hospice nurses have reported that patients in their last days will report vivid impressions of an impending trip by plane, ship, etc., suggesting that the subconscious can interpret a physical change like death (or leaving the body) in terms of conventional travel.
A very commonly reported dream is the one where you suddenly find yourself naked in public. The usual psychological explanation is that you have a deep-seated fear of personal exposure or public embarrassment, which comes out symbolically. This probably is part of it. But I wonder if the dream could also represent the ego's muddled interpretation of an out-of-body experience in which you suddenly notice that your "astral body" is unclothed, or at least not clothed in the usual way.
Then there is the old "oh my God, I'm back in high school" dream. No doubt it reflects, in part, unpleasant memories of one's formative years; but could it also represent a confused recollection of some sort of a learning experience conducted on the "astral plane"? After all, near-death experiencers, mediumistic communicators, and patients hypnotically regressed to a point supposedly "between lives" have reported that continuing education (so to speak) is a large part of their agenda.
At the very least, it is unusual that dreams about flying in levitating, traveling to new places, finding yourself physically changed (naked), and attending classes would be so common. Why these themes, and not others? And what is really going on when we're asleep?