I was walking back home when I looked at the sky and saw a star with a great bright. Around that star was a star-like light orbiting and after a few seconds it disappeared. A couple of minutes later when I was arriving home I saw a second light like the first one but flying straight. Behind that secong light was flying a very brighter light on same line and direction. Then, the lead light disappeared and seconds after that disappeared the "wingman" brighter light. I don't know what was any of the lights. It wasn't a plane (I know when I see a plane) and I think it couldn't be a comet or a death star because first one was flying in circles and others were flying on formation. A few seconds after watching the first light I started to percibe a sound like the hum that kept on my head till I arrived home. The sound was in the ambience.