i hope no one takes offense but i always thought that simulating smoke
or jet flame usually ended up looking pretty cheesy. if it's
purelly symbolic in nature, it's alright but if it's made to look
realistic, like that cotton jet smoke, it usually just looks bad.
if you're doing a jet taking off, it would look great to see the
ripples of flying dust layers on the ground, bending weeds, and so
on. if you're going for a plane in flight, it would look good if
the stand doubled as the jet exhaust representation, some great
potential there. i've also always wanted to make a model encased
in a clear plastic-type of material to be able to suspend objects and
"atmosphere" like smoke or fire in "mid-air" which would work great for
something like a jet, cannon fire or an explosion. anyway, of
course this is just my opinion.