Just recently someone in a discussion wrote that this video actually convinced them that chemtrails are real: Here, two planes fly almost parallel, and it is shown that their contrails have a well-defined starting point. They also seem to chase a third plane, which is, however, not contrailing. Please help me debunk this video. I know several similar videos and a number of explanations, including: 1. Plane flies from dry into wet patch of air. However, it seems too abrupt in this case. 2. Pilot suddenly increases throttle. There is a well-known video (debunked on this site) showing aerial refueling where this happens. However, there are two planes here and I guess they would not refuel simultaneously. I see no reason why they would go from no throttle to full throttle suddenly. 3. It's not a contrail but a smoke trail which is switchable by the pilot like in skywriting. This is possible in this case but I don't see the purpose. It doesn't look like skywriting or aerobatics. What explanation would fit this case best? Also, what are these planes doing? In fact, it looks like there is a fourth plane as well but I'm not sure about that. And what about the third plane not leaving a trail? Different altitude? I searched the forums to see whether this video was discussed before but I didn't find anything. It's a difficult case to me.