Bright Orange Lights moving quite fast at about 500 meters above the groundVery Orange lights against a dark night background. First three objects were sighted, following each other closely, moving from south-west into an easterly direction. They were moving quite fast and roughly 500 meters above the ground. After they have disappeared, a fourth light appeared and moved in the same direction and hight, but much slower. We could not identify any specific shape to the lights, but there was absolutely no sound coming from these objects!