How do the fighter jets in air shows color their smoke trails?
For example for the Patrouille de France under the Alpha Jet there is a tank called the smoke pod. Inside, two tanks contain oil with a colorant if you want color, or without colorant if you want white. When the pilot opens one of the valves, the oil flows through a small pipe and exits only at the left reactor. With the heat, around 700°C, it immediately turns into gas and gives this thick smoke. See this (in French):


Source: pilote-virtuel.com