Which of the following materials is commonly used in aircraft structures?

Aluminum is commonly used in aircraft structures due to its advantageous properties, such as its high strength-to-weight ratio, resistance to corrosion, and relatively low density. These characteristics make aluminum an ideal choice for constructing various parts of an aircraft, from the fuselage to wings, where minimizing weight while maintaining structural integrity is crucial for performance and fuel efficiency.

While steel is strong, it is also heavier, which can negatively impact the overall performance of the aircraft. Plastic can be used in some non-structural applications or interior components, but it typically does not possess the strength required for primary structural elements. Copper, although conductive and used in specific applications like electrical systems, is not suitable for primary structural components due to its weight and susceptibility to corrosion.

In summary, aluminum’s combination of lightweight and structural strength makes it the predominant material for aircraft construction.