I work nightshift at the airport and I as outside having a cigarette I'm always looking up at the stars as I have a telescope at home and u never know what o might see I also have a constellation app on my iPad and am interested in the constellations I . It happened the night of the meteor shower and I know it definitely wasn't a meteor I was looking up at Cassiopeia and the 3 star triangle in its formation when I noticed there was a fourth star making it into a square , I'm quite good with constellations and knew this wasn't right . . All of a sudden the fourth star started to move off fairly quickly towards the north east and then started to zig zag quite dramatically up and down back and forth at some speed leaving a thin wispy cloud like trail behind it . It wasn't a plane or helicopter as they do not work at night at aberdeen airport the only plane that comes In Is a freight one and it makes a very loud noise. What I saw was silent it way WAY to high to be a terrestrial aircraft. I watched it for about 2 minutes zigging and zagging around then it disappeared I felt quite scared seeing it because I had the strangest feeling it could see me aswell. Make of this what u will but I know what I saw. I didn't record it as I only had my phone and it wouldn't have picked it up