My husband and i were watching the skies for shooting stars, lightning bugs and airplanes. there were at least five planes that had come in from the south for landing at the local airport (possibly detroit metro). i looked up and saw a light in the sky which initially seemed to not be moving in any direction, as i watched it, it began flying in a straight path south-west. at first, i thought my eyes were seeing things. as i watched this light it started making erratic movements. a typical plane could not do this. the movements were too jerky and fast at this point. it shifted it's direction to begin going more directly south. by now, i asked my husband if he could see it, because i genuinely wasn't sure if my eyes were playing tricks on me. he confirmed what i saw. by now it was still going south but in a zig zag pattern. at one point we lost sight of it. i'm sure it's possible that this was a military plane. but i would point out, we've seen those as well, however, the flight pattern doesn't seem to match that of a military jet. in terms of altitude, our best guess is that which you'd expect a jet due to the size of the light (star), but it is just a guess. adding: we watch the skies on a regular basis, mostly just watching the stars and storms. and we've lived around airports most of our lives. so this stood out from the rest.