I don't know if it is implemented, but when you run and hit space to fly, you fly really fast. If you have a speed of 1 or 2 effect on you and you do the same thing, you fly as if you were running on the ground at the speed of 20. This bug only forks while you are pressing "W" and flying, if you let go of "W" then you will loose your speed and start flying as normal. If it is implemented then it's cool.