We are from the UK, and on our flight back from Majorca, Spain, on the plane when looking out of the window, we noticed a very long and unusually flat black object, I would say about 5 or 6 miles away from the plane, to my best approximation, guessing from the rest of the panoramic view I would say on a scale this UFO would be over 300ft long, definately not a normal aircraft I've ever seen in my life, as it was perfectly flat, and black. I am 16 years old from the UK, and I was with my brother at the time, and I would not go to the length of writing this description if I didn't believe it was something out of the ordinary. Obviously, as we were in the plane we couldn't view it for a very long time, maybe 5 minutes at the most, but it appeared almost stationary as our plane would be moving at a very high speed.