This is probably obvious to many, but some A/c have files under 1Kb, I figure those use a lot of default. Some are 5-7Kb and seem to have everything. But I have seen some from 38-192 MB (yes 192MB, AN-2 in Fsfreeware). Why such a huge difference?

Just depends on how they are done. For instance-the background bitmaps for the b33 deb are huge-the main bmp is 12 megs alone. The reason being it is made from a photograph-to reduce the colors would have compromised the "photo" look. Each of the side views are also done in a similar vein-80% of my file size is that.http://members.telocity.com/~geof43/geofanim2.gif

Ah..thank you. I knew there must be a reason :)