The ornamental design for a vehicleairdam, as shown and described.
FIG. 1 is a perspective view of a vehicle air dam, showing our new design.
FIG. 2 is a front elevational view thereof.
FIG. 3 is a left side elevational view thereof.
FIG. 4 is a right side elevational view thereof.
FIG. 5 is a bottom plan view thereof; and,
FIG. 6 is a top plan view thereof.
Stippling and tangency lines in the drawings represent the three-dimensional contours of the design, and are not intended to indicate surface decoration. The broken lines shown in the drawings depict portions of the vehicle air dam that form no part of the claimed design.