I have been looking through various gmax tutorials and tips, but haven't found answers to these two questions:

1. How do you animate leading edge flaps?

2. How do you animate jet engine nozzles so that they 'expand' with throttle as on most fighters? I tried to use non-uniform scale with the nozzle polygons with a 'scale' animation key, but the effect didn't show up in FS2002. The nozzle is an editable poly.

Thanks in advance for any help.

So far, FS doesn't support part morphing, only rotation and position animations work, so that is why your scaling animation didn't work. You'll have to design anything you want to animate so it will just rotate around an axis and/or move that that axis.

Here is how I would approach this. Think of the leading edge flap as you would a trailing edge flap but you are just looking at it from a different angle.

First center the pivot point to the flap Click on the "Heiarchy" tab, push the "Affect Pivot Only" button then the "Center to Object" button. In the top view move the pivot to the trailing edge of the flap, constraining to Y and zooming in as tight as you can on the pivot point center. Do the same in the front view till the pivot points center is right on the edge. Remember that if you use an edge snap, you won't be constrained to Y. Just have to zoom in and eyeball it. Once you have the pivot center in place you can rotate the pivot around the Y axis to line up with the dihedral angle of the wing. Once that is done go back to top view and rotate so the X axis lines up for the sweep. Once you have these set, UN push the "Affect Pivot Only" button and the part is ready to animate.

SAVE YOUR WORK NOW!!!

I also find it a good idea to lock the current selection so something else doesn't accidently get selected and I don't have to have the cursor right on the part.

As far as the animation it self goes, that is something you kinda have to play with till it looks right. (slide forward and rotate downward. Try various controllers and different key frame divisions. Remember that a key frame is what the controller uses as it points of reference, like a starting and target point. The more key frames you have the more control YOU have over what is going on because the controller is constrained by the information you put in at the key frame... position and rotation values. All the controller does is interpolate  the values of the non key frames base on their built in formula.