Airfoil

FIG. 1 is a top perspective view of an airfoil, showing my new design;

FIG. 2 is a front elevation view thereof;

FIG. 3 is a rear elevation view thereof;

FIG. 4 is a left-side elevation view thereof, the right-side elevation view being a mirror image thereof;

FIG. 5 is a top plan view thereof; and,

FIG. 6 is a bottom plan view thereof.

The broken lines shown in the drawings depict portions of the airfoil that form no part of the claimed design.