I recently created an aircraft powered by Andrew Linden's flight script and I had a problem with it - the plane would disappear from under me, and over the course of the next 3 days, I got it returned to me a prim at a time by autoreturn from a dozen different peoples land - and that included the particle generating noisy engine which landed in someone's garden who was away and it annoyed the hell out of the people next door until they could get hold of me to come and delete it.
I believe this is caused by going over land and exceeding the prim limit for that particular piece of land.
It occurred to me that it might be possible to to avoid this problem if I wore the plane as an attachment.
Does anybody have any experience with this?