Witnessed approximately 20 bright white lights in a diagonal line across the sky shift to be vertical and then one at a time disappear

While driving I witnessed approximately 20 bright white lights in a diagonal line (at about a 45 degree angle) across the sky. They appeared to be about as high as an airplane would fly. Maybe higher. They looked like bright stars (white lights) but much closer than stars. They were equally spaced apart. I pulled over to watch them and they began to slowly move (maintaining their equal distance apart from each other) from their diagonal line into a straight vertical line. The top light then started to move a little bit away from the others straight off the top of the line and then all of a sudden it shot off and away from the others. Then the next light would do the same. When they shot off it was so fast that it looked like a shooting star and disappeared. Each one of the lights followed suit until they were all gone.