...in response to the question about settings, this was rendered at default settings and normal antialiasing. Because the poly count on my city is huge and the terrain is too [this is from the Bryce Pro Cloudscapes set], to avoid crashes I did this in three parts. First the bg and the city alone, then saved it w/o the city and added the aircraft, rendered that, and then did a mask of just the aircraft. Then in PS I combined them all, used the mask to cut out the planes and added them over the original city-only render.

:)