I was inside my home watching tv and heard a very loud jet like sound overhead. it was very loud sounding like maybe 4 jets flying together. i live in napa county california and have recently observed unidentified objects in the sky at night. i quickly grabbed my iphone to try to get a video of this thing. i ran outside and could be heard saying, "what the hell is that? " "what is that?" but all of my neighbors were inside. i began the video and (at first) i noticed i was pointing the camera a little to far to the left and then the triangular object came into view. it was flashing and traveling south. it wasn't that high in the sky but it was moving away from me. i noticed the flashing lights and different shades of blue and gray. may have been different metals. i tried to make sure i followed it with my camera. as it moved away from my sight it turned left and began traveling east. i took as much video as i could and have not reviewed it yet because i wanted to report this as fast as possible. i will attach the video. anyway, i have seen a few ufo's (flying very low) since moving here. i am frightened by this because i was not a believer until i observed a ufo that was very close. this ufo was not the same one as before. each one i have seen has had blinking lights but the shape varies. they fly very low which is why i see them so clearly. previously they were silent. this one tonight was extremely loud. i do live by an airport and know what i saw and heard. this was not an airplane or helicopter. nor was it a drone or weather balloon. our airways are monitored and i believe they would have seen this thing. i would like confirmation of this incident. i did watch it until it was out of sight due to houses and a hill. i want to mention that i heard the same sounds later tonight while typing this but did not see anything in the sky. i did observe a white streak across the night sky a little later which is not something usually seen at night. it was not a cloud. i tried to capture it on video but do not know if i got anything. i will also submit that video.