Not only has the quality of cameras increased increadibly in the last decades, especially thanks to modern digital cameras, but in the last 10 years, most of us are carrying a quite good camera in their pocket all of the time. This would easily allow for documenting any strange phenomena. And that this works is shown. When the meteor struck chelyabinsk some years ago, there where plenty of videos thanks to dash cams. When recently debries of a SpaceX second stage reentered the atmosphere near Seattle, there were plenty of videos taken showing this event. This is not even taking into account all the advanced amateurs, who are shooting images of the ISS in orbit, or even any professionals, whose job it is to track the air and space around earth for things. Any metal part in orbit is tracked by NORAD for obvious reasons.
So, where are such videos showing the aliens? It is obvious, that people constantly are seeing things which are not directly explainable, especially to non-scientists. But somehow they are not recorded. One good explanation is: a lot of them are recorded and in the record, they are easily identifiable as what they really are and no longer mentioned.