I've had this sensation for well over 10 years now. It's not every night of course, but it's not rare either.
It seems to happen mostly when I am dreaming of floating, flying, rapidly descending, or something scary.
Sometimes, I can actually control where I "fly" to a certain point, and then the scenery changes. Therefore, I am skeptical of the "out of body" experience.
A lot of the times I will force myself to wake up, probably as a security thing, and within 5 minutes of closing my eyes again, it continues.
Additionally, I feel like I'm not in a deep sleep. Sometimes I can (or think I can) hear what is going on around me as I sleep while this is happening.
I personally think it's pretty cool, because it's differen't from any sleep experience I've ever had. As long as it doesn't have anything to do with a health risk, I look forward to the next time I dream like this.
I too, thought it might be something in the way of an out of body experience at first. I am open minded and although I hold my beliefs true, I find it educational to talk with others who believe in different things.
However, I never have to "return" to my body, nor again can I completely control the direction of flight or fall 100% of the time.
I have talked with someone who believes in out of body experiences and they informed me of transportaion facilities as in airports, etc and I've never experienced that. My reply was, "If I could fly myself, why would I need a plane?" =D
I'm not saying it doesn't exist, I'm just saying I've never experienced anything like what was explained to me.
Hope this information helps, and I look forward to reading more responses on this because I too, thought I was in a very low percentage of people who experienced this sort of thing.