Unknown Objects Photographed over Cologne, Germany

I was having an evening meal with friends (Cologne, Germany) on the 10th of May this year. Suddenly my sister noticed an object flying over us (we were on a balcony) at a huge speed (too fast for a balloon) and emitting no sound. The object flew in a straight line past us. After that object had passed, another object followed it.

ufocasebook.com