The development of an aircraft noise‐suppression system is essential to the relief of communities adjacent to commercial airports that are adversely affected by jet‐aircraft noise. This paper is a brief review of the structural aspects of current turbofan noise‐suppression designs presented in conjunction with a summary of the environmental conditions that determine the design criteria of duct‐lining materials. Also included are: (1) prospective drawings of the various acoustical sandwich configurations; (2) descriptions of the porous sheet, honeycomb core, and adhesive materials that compose the composite configurations; and (3) a discussion of the special structural and evironmental tests required to develop the mechanical properties of acoustical materials.