Here's a story from my youth. I must call it an "UFO" as it was flying. This story takes place in Northern CA, in a small town. The sorrounding area is undeveloped farm land. This siting took place in my back yard at around 1 am. I was a 13 years of age. My house was on the outskirts of a small neighborhood across from miles of hay field. My twin and I were spending the night on our trampoline it was a warm clear, starry summer night. We couldn't sleep. I remember looking out towards the field into the sky when I saw a large shape moving parallel towards where we were laying. It looked as though some one had created a ripple in the fabric of the night sky and stars. I could see the outline of the mass in the sky, but not the mass or craft it self. It's very difficult to describe as we just don't see things like this. It was see through, yet I could make out that it was a large shape. I vaguely remember that it moved with the grace of something with wings. As it moved it displaced the appearance of the night and stars. it moved with grace and fluidity- like an ocean wave. A see through wave. Where it's mass should have been the fabric of reality took on a fluidity and wave like appearance, yet I could make out form. This beautiful thing gliding in the sky had form. To me, it moved like it was alive. It crossed directly over us on the trampoline and continued moving across the night sky towards the mountain range we lived near. I watched it go until I couldn't see it any more. When something is invisible it's hard to say how far up it was- It did appear to be about a telephone pole or two above us. This wasn't happening in space. It was happening right over me. I wasn't scared, which was surprising because I was afraid of everything as a child. My twins story in comparable. We spent the night out on the trampoline again that summer and saw it three more times always moving over us towards the mountain range. I'm 30 now and never forgot it. We called it the "batman car bird" as kids because that's what it looked like.