Depends on the scale. Really tiny microorganism living in the air do not fly, as in they have no active mecanism to physically interact with their environment to move in any way. They just follow the air currents at seemingly random (the exact word is brownian), kinf of like particles of dust that you see in a ray of light. It is not defined as flying and not studied as such

Yeah I understood after, hence my very fast edit to add the last sentence about flies existing only from around 245 my

Insects fly the same as birds and aeroplanes do, they create air flow around a rounded wing edge, wich causes the air upward of the wing to flow faster than the air under, thus creating a lifting force. And to answer origins, to our knowledge insects were by far the first living flying things, around 300 million years ago with dragonfly relatives. And the group including flies (diptera) came much later, around 240 million years ago !

Why are you still trying to get people say that street racing is OK ? You tried several times, framed the question many ways, and are reduced to comparing it to another terrible selfish behaviour to try and have a smidgen of validation… That’s kind of sad actually, when you ask questions, you should have the courage to face any answer, not just the one you wished for, and respect that