Player movement physics

Hi, I have been seriously considering creating a new flight mod that is not a creative flight type mod.

This would figuratively imply player movement physics such as: momentum, air friction, gravity e.t.c. ^{these values would change over time or by player input.}

I tried searching the internet and especially this site for some potential hints on how to do this. ^{I was not able to find anything except some bits of info on vector overwrites and creative flight mode.}

So far I believe that I would have to play around with vectors,

although I have no clue where I can find more information on how the player movement physics work and which mappings are concerned, e.g. swimming, slow fall, momentum etc.

Could someone please help me getting more info on this, that would be really awesome?

Thank you! :)