From previous modding of other games origin/angles/speed is always taken into account for path-nodes (AI/Vehicles/Aircraft etc) and is accessed by a global script.
Example ...
Spawn info_splinepath "targetname" "planepath1" "origin" "x x x" "angles" "x x x" "framerate" "XXX"
(I dont know how your adding the paths in GE but id say theyll be similar in how they link up).
I know this might not apply in GE and is pretty basic but im just throwing some ideas your way that may (or may not) be useful
