While spending the weekend with my Dad in Camp Verde AZ, I went outside at about 9pm. While standing outside I saw something moving slowly North to South approximately 100 ft away and about 100 ft up at the closest point. It was not making any sound, just slowly moving from my left to my right. It took about 20 minutes from when I first noticed the lights until suddenly the direction changed from North to South to head East suddenly at a right angle and increased speed and disappeared from sight in less than a minute. I was aware that whatever it was, was not a plane or helicopter. There was no sound or wind and was moving too slowly to be a plane. I was not scared, just amazed. It was like nothing I had ever seen before or since. I went inside and told my dad. He said it was probably a helicopter, and laughed when I tried to explain how it moved and disappeared. I shut up and dropped the whole thing. I have not reported this before because I did not want to be laughed at again. I lost sight of the object when it suddenly made a right angle turn and accelerated quickly to the east.