If I saw this out the window of a plane, I’d be a little bit terrified:
This seemingly horrifying scene is the result of the way that images are captured by the sensors that we find in many modern smartphones.
Unlike real film cameras, active pixel sensors (like those found in many smartphones) don’t expose every pixel at the same time, but rather, do so in sequence. While the consequences of capturing photos this way is trivial for most things, objects moving at high speed may seem to exhibit some strange behaviors, like the propeller above which appears to be literally falling away from the airplane.
This is definitely tough to explain with text alone but you may find this visual explanation helpful. In the video, the line that moves from the top to the bottom represents the sections of the sensor that are actively capturing data: