The ornamental design for a tray for a portableair compressor, as shown and described.
FIG. 1 is a perspective view of the tray for a portable air compressor, showing my new design, wherein a portable air compressor, which is shown in broken lines and forms no part of the claimed design, is mounted on the tray for inflating a vehicle tire, e.g., on sand;
FIG. 2 is a perspective view thereof;
FIG. 3 is a top plan view thereof
FIG. 4 is a bottom plan view thereof;
FIG. 5 is a front elevation thereof, the rear elevation being a mirror image; and,
FIG. 6 is a left side elevation thereof, the side opposite being a mirror image.