What is the key characteristic of composite materials used in aviation?

The key characteristic of composite materials used in aviation is their high tensile strength. This attribute allows composite materials to withstand significant forces and stresses during flight, making them ideal for various aircraft components where both strength and weight are crucial factors. The combination of different materials in composites, such as fibers embedded in a resin matrix, provides excellent performance in terms of strength-to-weight ratio. This enables aircraft to achieve better fuel efficiency, increased payload capacity, and improved overall performance.

While other options may present certain attributes, they do not capture the essence of why composites are favored in aviation. For example, heavyweight materials would be detrimental in aviation, where minimizing weight is essential. Magnetic properties are not generally a desired feature in aircraft materials, as most composite materials are non-magnetic. Low cost could be a consideration but does not characterize composite materials specifically, as many high-performance composites can be expensive due to their manufacturing processes and material sourcing. The focus on high tensile strength underscores the importance of structural integrity and performance in aviation applications.