Refer to figure.
Sandwich structures are lightweight, high-strength materials used in aircraft construction. They consist of three main layers: a lightweight core, usually constructed in a honeycomb form, sandwiched between two thin, high-strength "face sheets" (typically aluminium, titanium, or composites like carbon fibre).

They are highly use in aircraft primarily because of their:

• High Strength-to-Weight Ratio: The combination of a lightweight core and strong face sheets provides excellent structural strength while minimizing weight—critical for aircraft performance and efficiency.
• Stiffness: The structure resists bending and deformation, making it ideal for aircraft components that must withstand aerodynamic and structural loads.

However, they may need to be reinforced in areas to carry concentrated loads, and their high stiffness does not make them useful for components which need to absorb certain variable forces.

These qualities mean that sandwich structures are well used within many aircraft, such as for:

• Floor Panels
• Control Surfaces
• Fuselage Panels
• Wing Components
• Sound Proofing Around Engines