When homeless near Stranraer in south west Scotland, I was on a flight path from airplanes taking off (presumably) from Prestwick airport but the airplanes were so high, you could only see their shape and exhaust trail. however after a few weeks their altitude dropped so they were at full throttle only a few hundred feet above me making a terrible noise and at that height you could see their livery quite clear. They were ALL Virgin Atlantic planes! Similar stuff was happening when I was in London, Heathrow's take off moved as I moved along the Thames.