The mission editor is always included with recent versions of Aces High. I learned how to use it by studying the "Help" that's included with it (especially the "tutorial"). Within about 2 weeks I was able to write fairly sophisticated missions. I hope your experience is at least as pleasant as mine.
![salute :salute](http://bbs.hitechcreations.com/smf/Smileys/default/salute.gif)