General Discussion

This was not a case of drones just colliding with each other. With a quadcopter-type drone, if there is physical damage, it does not fly far away. It will tumble and fall to the ground.

It is hard to know what the formation was supposed to look like, but it appears to be somewhat uneven and sloppy. Not at all like other shows performed by this same company.

More telling is that you can see a couple that move out of the formation, then recover and fly back to the correct position. That is not what happens if they collide. It looks like controlled flight the entire time. So either they are being commanded to do that, or they are getting bad sensor (GPS) data about their location. I believe it is the latter and when the interference goes away, they recover their location data and move back into position.

The ones falling straight down are likely from collisions in the air caused by drones being out of position, again due to GPS interference.

Drone shows are almost entirely pre-programmed. They are not being commanded live from the ground. Perhaps at a high level (takeoff, go to formation 1, go to formation 2, etc.), but the flight paths are all preset, so it isn't likely that this was an issue with control communication from the ground. So that just leaves bad sensor data as the likely cause.

GPS jammers are cheap and easy to get. The GPS signals are so weak, it is relatively easy to overwhelm them. There are jam-resistant GPS sensors, but they are very expensive and still limited in what they can deal with.