Exaclty. Also, a missle doesnt really show flames in its' trail, just a super-hot red/blue glow, that quickly tapers to smoke/steam.
A rocket, or meteor will have flames before the smoke, so is that what you are trying to do?
If you look at the pic below, I made this trail using a basic particle cloud renderType, and just tweaked the colors/intensity in layers in post.
Israel "Izzy" Long
Motion and Title Design for Broadcast-Film-DS