In this paper, the unsteady three-dimensional thin-layer Navier-Stokes equations in the moving frame of reference are solved by using a time-accurate implicit approximately-factored finite-volume scheme. The steady results for a delta wing of aspect ratio of 1 and 20.5° angle of attack are compared with the experimental data of ref. 18 . With the steay results serving as the initial conditions for the pitching motion the problem is solved. We present comparisons between the Euler equations solution and the thin-layer Navier-Stokes solution for both the steady and unsteady flows.