ah... racing and planes.. an interesting combination

But racing with planes will probably end up flying a straight line between start and finish, and that doesn't sound spectacular. :eh:
How are you gonna solve this??
You could e.g give planes a maximal height and make large moutains that exceed this maximum height and function like wallsin a maze game. This way you let the planes race through some kind of valley.
When you focus on graphics, this concept may yield some nice views of valleys with large slope forests and steep rocky cliffs.
I already have that picture in mind

And what kind of finish are you going to use... a ring, line on the ground, a large plane/surface or an airport?? :?

eh.. another idea:
When planes fiies high enough to get over the mountains (walls)... they will be taken down by a seeking missile before they reach the finish. :lol:

Hope these idea's are usefull... Good luck

BTW... hope you get SCAG finished soon.. you have put tons of time and effort in it so it would be a shame if it doesn't get done.