quick knockback rules question

[Thac0 Redeye]

I have a low level barb. he is being built to be an uber charger. currently I have imp bull rush and knockback. Last session we were fighting a flying creature. I was able to charge and do a running high jump to hit him. When I hit i also did a knockback. we just used the same rules as if he was standing. Is there special modifiers to use in this case? I couldn't find any where.
Thanks

[Venger]

You knock the flying enemy directly away from you as normal. In that regard, there are no special rules imposed by them being flying. If what you're asking is do you knock them back purely on a 2 dimensional axis horizontally away from you, the answer is probably not. When jumping, you move in a perfectly symmetrical arc reaching a vertical height of 1/4 the horizontal distance covered, so from that you can extrapolate whether you are striking a flying enemy from above or below and knock them diagonally in the correct direction up or down. If you're at the same vertical height, you'd knock them straight back without changing their elevation.