Display aircraft usually have a tank that holds coloured diesel, which is injected into the jet exhaust. Quite often you can smell it at airshows although I'm not sure if the diesel actually burns it obviously gets hot enough to produce smoke.
It used to be diesel. Many display teams are now switching to vegetable oil because it is cheaper and has less environmental impact.
Diesel is still used by some teams. Either the equipment needed is different or not all colours can be produced using vegetable oil.
Yeah I heard it was something like that I just needed to confirm it...as I'm actually doing a speech at school on the RNZAF skyhawks (the top two pictures above)
So does anyone know a different name for it?