A wing skin is usually mounted to a support structure by using metal fasteners which cause high stress points and potential leakage points. The invention utilizes projections formed in a wing skin to mate with recesses formed in a support substructure which, when positioned together, form interdigitations which prevent sliding displacement of the wing skin. A plurality of sliding bars transversely pass through the interdigitating sections to maintain an interlocking relation. The transversely oriented bars enable the use of the invention with contoured wing skin structures.