In the present study, the aerodynamic characteristics of elliptic airfoils were numerically investigated based on the Reynolds-averaged Navier-Stokes equations and the Spalart-Allmaras one-equation turbulence model. Calculations were performed for several Reynolds numbers between 2.48 x 10(5) and 3.91 x 10(6) at freestream Mach numbers ranging from subsonic to transonic. The formation of the leading-edge laminar separation bubble and the flow separation characteristics at the trailing edge were studied, including the effects of Reynolds number and compressibility. Elliptic airfoils with different thicknesses were considered for the investigation of the thickness effect. The results were compared with those of NACA series airfoils with identical thicknesses.