With their high stiffness and low weight, honeycomb materials are becoming an increasingly important element of advanced aerospace design concepts. For example, honeycomb materials have found usage for noise damping and abradable seal applications in modern jet engines, and actively cooled honeycomb structures may be the basis of wing and fuselage design for the proposed national aerospace plane. Numerous factors influence the applicability of metallic-based honeycomb structural materials for different applications, including availability, manufacture and cost.