There are a few problematic assumptions in this line of thinking: you assume the event is as dramatic as a meteor or explosion, occurs in a highly populated area, and involves no discretion on the part of the object. This is typically not the case, although you could argue that people recalling the same specific details in smaller witness groups, but across many different incidents, could constitute the same idea. Even with this in mind, I can think of a few truly mass sightings.
https://en.wikipedia.org/wiki/Phoenix_Lights https://en.wikipedia.org/wiki/Belgian_UFO_wave https://en.wikipedia.org/wiki/Petrozavodsk_phenomenon https://en.wikipedia.org/wiki/1561_celestial_phenomenon_over... https://www.bbc.com/news/magazine-29342407
And you should read these if you are interested in an account where either the Navy fabricated this weird hoax, fake data and got a squadron of pilots to lie about it very convincingly, or the whole event is real. Multiple radar, multiple pilot visuals, multiple angles.
https://www.nytimes.com/2019/05/26/us/politics/ufo-sightings... https://www.thedrive.com/the-war-zone/33371/here-are-the-det...