Very large regtangular object blocking out the stars with an almost inaudible but loud sound?

My memory on the event is a bit sketchy, however I do remember the most relevant details.  I was about 12 or 13 years old at the time, and my friend was travelling with me, my mother and her boyfriend back from town.  He was staying over at my house that night celebrating our birthdays and being a warm night, decided to sleep outside in the camper.  Being in a rather darkened area, travelling down route 209 from Parrsboro to Kirkhill, I regularily star gazed.
 It was an extremely clear night with the sky lit up with stars.  I focused on approximately 8 - 12 objects in the air, about the distance of a plane but no flashing lights.  They were just lit objects in the air.  They travelled in and out of formation quite a bit, travelling much faster than any plane I had ever seen.  We watched them all the way home for approx. 3 miles.
 Once arriving home, we never really thought about them again and went into the house.  We then shortly went outside to the camper, and with the power connection began playing nintendo.  We were concentrating on the game and talking when we noticed what seemed to be a "silent" engine get louder and louder (I say silent because it got louder so gradually that it was hardly noticable).  We looked outside at one point, towards the north above the "mountain" side.  Being such a clear night, we could see a shape in the sky that blacked out the stars around it, above the trees.  It seems almost surreal as when we were looking, it was as if it sensed us and backed over the trees and mountain.  This happened several times over the next hour.  We weren't really afraid, more intrigued.  At one point we fell asleep, not knowing if it happened again throughout the night.
 I just remember it being very large, blocking out starlight, (10-15 meters wide, 75-100 meters long), and having such a strange engine sound to almost not have a sound.
 Just wanted to share one of my experiences in this area.
Time and date are approximate.  PD