Oval bright white light, traveling fast for about a minute, then disappearing.

As I´m standing on the rooftop of my building, I see a bright light approaching.  
At first I thought it was a fast moving plane, but as the travel path of the light changed in angles (moving from right to left, a plane light would have diminished and it's wing signals become visible), it was the same intensity (bright white), with no blinking "airplane" lights. 
It travel from my right to my left, for about one minute, before dimming rapidly and disappearing.