Ceramics are used as insulation on aircraft because they are corrosion-resistant, heat-resistant, and:

Ceramics are an excellent choice for insulation on aircraft due to their lightweight properties, which contribute to overall fuel efficiency and performance. When considering materials used in aerospace applications, weight is a critical factor; lighter materials help reduce the overall mass of the aircraft, enhancing its efficiency and maneuverability.

In addition to their lightweight nature, ceramics provide significant advantages in terms of corrosion resistance and heat resistance, making them suitable for high-temperature environments commonly found in aircraft. This combination of properties helps ensure that the insulation remains effective and durable over time, minimizing maintenance needs and improving operational lifespan.

The other options do not align with the characteristics desired in materials for aircraft insulation. Heavy materials would contribute unnecessarily to the aircraft's weight, flammable substances would pose safety risks, and electrically conductive materials would be unsuitable as they could interfere with sensitive electronic systems and lead to complications such as electrical shorts. Thus, the lightweight nature of ceramics complements their other beneficial properties, solidifying their role as a preferred insulating material in aircraft design.