The object in the video of the event is roughly the size of the elbow-to-fingers of the woman below with her arm on the railing, which is around 1.5 to 2 feet for men. For women it’s shorter, around 1 to 1.5 feet. The object is not flying directly over their heads, so it it is closer to the camera and will be smaller. If we use that distance as the maximum, the object probably isn't more than around 30 cm long. For its minimum size: 8 mm, the size of an average housefly or a smallish horsefly (which range from 0.5 to 2.5 cm). In the first frame (0.0333 seconds), the object moves about 36 times its length. This gives possible speeds, roughly, of:
Length: Speed
30 cm:
705 mph
2.5 cm: 59 mph
8 mm:
19 mph (or 8.4 m/s)
In the other frames, it only travels around 21 to 22 times its length for a total of 104 lengths (in the 0.1332 seconds between first and fifth frame). Assuming a straight line parallel to the camera, that gives average speeds of:
Length: Speed
30 cm:
524 mph
2.5 cm: 44 mph
8 mm:
14 mph (or 6.25 m/s)
Horseflies can fly
up to 90 mph or 40 m/s. (Incidentally, the fly in the
video Mick West used for reference moves 33 body lengths in one frame, faster than 3 out of 4 of these frames.)
If you watch the full video of the Utah event above, you can find plenty of other "mystery drones": e.g. at 0:37, 2:19, 2:20, 4:43, 6:23, 10:42, 11:29, 12:28, 14:02, 14:58, 15:45, 16:14, 17:19, 17:48, 19:05, (gunshot is at 19:09,) 19:40, 19:52 is the totally-not-a-bug "drone", which shows up again for a single frame at 20:00, 1.5x bigger (bottom right image in collage below). The place was positively swarming with "drones". And that was just the obvious ones in the first 22 minutes. I’m sure if you focused on areas below the skyline there would be more.
Except for the wispy fluff at one of the times above, it's obvious when you watch that these are all bugs. Here’s a collage of some of them:
Here are some horseflies next to the Utah drone for comparison. I couldn't find a picture of a horsefly flying at the exact angle of the video, but you can use your imagination. Just rotate the horseflies in your mind:
As for the Butler “drone”, it travels about 19 times its length in 0.0333 seconds.
Length: Speed
30 cm: 383 mph (just multiply this by however feet long you want it to be to get your speed estimate)
2.5 cm: 32 mph
8 mm: 10 mph (or 4.6 m/s)
Here are the two frames from the Butler video. The middle image is a duplicate of the one on the left with highlights turned down to bring out the darkened bits on the top and bottom. At least the top shadow looks like a bug wing to me, as does the wing in the right frame:
There are even more bugs in the realDJStew Butler video, e.g. at 3:21 for two frames, 3:23 for one frame, 4:51 for two frames, 6:00 for eight frames, 6:09 for eight frames, 7:07 for two frames. I remember when I watched the bodycam videos closely that at least one of the ones from on top the roof has a couple big bugs flying by (in front of the taller building, so there's no mistaking them).
Some flying bugs from videos of swarming
horseflies and
bees:
