1-1/4", 1-1/2" and 2" wheels (all with 1/4" axle holes)
Make pattern from print of Cars by gluing to a piece of cardboard. Cut pattern to shape. Pattern can also be made from mylar or 1/8" masonite.
Draw shapes on wood surface and mark axle and other hole centers.
Drill 5/16", 9/32" or 17/64" holes for axles.
Drill 5/8", 3/4", 1" and 1-1/4" holes for windows.
Saw body from 2" x 4" or 3/4" lumber (sand sides smooth). Fill any voids, cracks or knot holes with filler.
Sand curved surfaces with an orbital sander to smooth.
Smooth all sharp edges with a 1/8" round over bit or break the sharp edge with sandpaper.
Cut ¼" dowels to length (body + 2 x wheels thickness + 1/16" or 3/32" clearance). It is important to taper the ends of the axles to get them to easily go into the wheels. An easy way to do this is to gently sharpen the axles by turning the sharpener backwards in an old fashioned pencil sharpener-much easier than trying to do this with sand paper.)
Assemble wheel to one end of axle using white or yellow glue (Hot melt will not work.) (An easy way to glue the wheels to the axle is to dip a pencil point into a pool of glue and use the pencil to spread the glue to the inside of the wheel axle hole.) Add second wheel to complete assembly. Test that wheels turn freely.
Rub your hands over the entire vehicle to make sure there are not sharp edges or points. Remove with sandpaper if any are found.