I personally wouldn't touch the DBP particle system with a barge pole. Here's a temporary shot of something I was working on last night (temporary as in, it probably won't be
here next week). You use lots of small plains, textured, ghosted and point them towards the camera.
The advantage of this method is that through very simple commands, you can create interesting effects. That purple thing on the right for example, All the billboards rotate around the square's centre, rise and fade. It looks a bit like a fire, only not.... For a jet, I'd scale the billboards randomly, per frame to give that chaotic, shimmery effect.
...and the rest is f-l-y