Plastics have evolved into sophisticated food packages. This evolution requires flavor management from the package. Flavor loss can occur from a variety of mechanisms. Of particular interest are flavor losses that result from interactions of flavor molecules with the package. This paper presents the permeability, P, and the component parts, the diffusion coefficient, D, and the solubility coefficient, S, for selected flavor molecules. Use of these parameters to estimate flavor loss is included. The effects of temperature, humidity, concentration of the flavor, combination of flavors, size of the flavor molecule, and type of flavor molecule on the diffusion and solubility coefficients are discussed.