Creating an anti exploit for flying

[starmaq]

FJ's (Experimental) Character Anticheat

I created an experimental anticheat system that heavily curtails common movement cheats like speeding, teleporting, noclipping, flying, and ludicrously-fast spinning. It does this by using a set of “heatsinks”, which quickly gain heat while a player is displaying anomalous behavior, as well as a set of assumptions, such as players only being able to jump a certain height off the ground. Upon determining a player is cheating, it teleports that player back to where they were last time they were …

This might help.