The ornamental design of a countertop for a commercialaircraft passenger cabin lavatory, as shown and described.
FIG. 1 is a perspective view, taken from a front, left side, showing a countertop for a commercial aircraft passenger cabin lavatory according to a first embodiment of our design;
FIG. 2 is a top plan view thereof;
FIG. 3 is a left side elevation view thereof;
FIG. 4 is a right side elevation view thereof;
FIG. 5 is a front elevation view thereof;
FIG. 6 is a perspective view, taken from a front, right side, showing a countertop for a commercial aircraft passenger cabin lavatory according to a second embodiment of our design;
FIG. 7 is a top plan view thereof;
FIG. 8 is a left side elevation view thereof;
FIG. 9 is a right side elevation view thereof; and,