The ornamental design for a powerunitattachable to a folded paper airplane, as shown and described.
FIG. 1 is an isometric view from the front, above and one side of a power unit attachable to a folded paper airplane showing my new design, (opposite side is identical);
FIG. 2 is an isometric view from the rear, above and opposite side;
FIG. 3 is a side elevation corresponding to FIG. 1:
FIG. 4 is a side elevation corresponding to FIG. 2;
FIG. 5 is a top view;
FIG. 6 is an isometric view from the front, below and the one side;