At some large military parades or airshows, there will be tiers of fighters arranged neatly. In order to increase the visual effect, white or colored smoke will be sprayed from the tail of the fighters. How is color added to the smoke?
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):