So this is a "threat"? Hmmm.
Your smoke trail is the same size from the beginning to the end. Look at the way the jet trail increases in size from the back of the plane to the end of the trail, then look at your black smoke. You'll need to set the time & scale properties to adjust for those.
Dave Baer
Professor of Digital Arts
Digital Media Arts College
Boca Raton, Florida
dbaer@dmac.edu