I'm not sure, but if you want it already flying it might be easier to setpos it in rather than createUnit it.
To do that, create a flying chopper at an obscure corner of the map and name it as you like. Create your marker. At the appropriate moment:-
AH1 setPos getMarkerPos "here"
You might need to experiment with giving it waypoints (before/after the setpos) to get it going the right way, or possibly use setVelocity.
It's easy to give a unit a name when you are using createUnit. In the bit for the unit's init field write
this = AH1
I think that's right, anyway. You can certainly do it in the init field. Dunno about the special field though.