The ornamental design for an aerator, as shown and described.
FIG. 1 is a top, front, perspective view of an aerator showing our new design, with a top, rear, perspective view being identical to FIG. 1;
FIG. 2 is a front elevation view thereof, with each of a rear elevation view, a left side elevation view, and a right side elevation view being identical to FIG. 2;
FIG. 3 is a top plan view thereof;
FIG. 4 is a bottom plan view thereof; and,
FIG. 5 is a bottom, front, left side, perspective view thereof.
The short dash-long dash broken lines in the figures illustrate boundaries of the claimed design and form no part thereof. All other broken lines illustrate portions of the aerator that form no part of the claimed design.