1.On May 8, 2013, at 7:45pm Toronto time, West Jet flight 629, the plane was descending to Toronto Pearson airport for landing, and traveling at 361mph and 5500 feet according to the information/entertainment display screen behind the seat.2.My window seat number was 3F. When I was looking out the window and saw an object went from the front to the back. I couldn't tell the object was stationary or was moving. A boy (about 7 years old) sat behind me was looking out the window, at the same time, and he was saying "What is that?"3.The object was in clear view and around 1000 feet below the right side of the plane. It was square, had no wings, beige in color, and relatively big. By comparing the object with the jet engine view, the cross section of the object is about 10% of the jet engine air intake diameter.4.The whole event lasted for 1 second. It was an amazing sighting and a second seemed quite a long time.5.A drawing is attached.