Large UFO flew over treetops above the house emmitting LOUD reverbing zip gun sounds.We heard "it" go over the house..you could hear a huge rushing sound of air..there was a LOUD continous sound that sounded like a zip gun from a sci-fi movie..like a reverbing, siren sound.....the thing had to be very large and traveling just above the treetops..it was very low..you could hear that rushing sound of air...but no motor sound..we live under a flight path of sorts..and we know what all make of aircraft sound like..this was nothing like anything we'd ever heard. Please advise if anyone else has heard this sound before from a ufo. By the time I got to the other side of the house it was gone..my mother was frozen to the couch..she didn't try to get up to see it..she thought whatever it was ..was going to crach into the house.So we didn't get to see it..but I'm watching for it now.((NUFORC Note: Witness is semi-anonymous, providing just an e-address. PD))