Bright lights doing 90 degree turns over Rhein Main Air Base

While stationed at Rhein Main we were experiencing lights in the sky above that were darting around doing 90 degree turns at very fast speeds.  It was well known on the base that they were being seen every night so I am suprised no one else has reported it.  
I had my two brother in laws visiting from the states and told them about it and they did not believe me so I pointed up to the sky without even looking up and told them to watch.  
They saw the same thing we had been seeing and it scared them so badly that they just wanted to go inside.
Date may be approximate.  PD