Measure the width and length of the mattress with the tape measure. Make a note of the measurements.
Cut one 2x4 board to the width of the mattress and two to the length with the circular saw. A fourth board will need to cut that is two feet longer than the width of the bed.
Form a frame by assembling the boards in the shape of a rectangle. Align the longer board so that there is 1 foot on each side of the frame.
Drill two pilot holes with the power drill at the corners where two boards meet. Secure the boards with screws.
Draw an outline of the wings for the spaceship on a sheet of 4-inch by 8-inch plywood. Cut out each of the wings by following the outline with the jigsaw. Sand the cut edges smooth with the sandpaper.
Place the one wing on the edge of the 2x4 frame and drill pilot holes with the power drill. Secure the wing to the frame with screws. Repeat this step with the other wing.
Trace an outline for the rear of the spaceship from a second 3/4-inch sheet of plywood. This rear piece will need to match the width of the mattress. Cut the plywood with the jigsaw and then sand the edges using the sandpaper. Secure the rear of the spaceship to the back of the 2x4 frame with screws.
Cut out two pieces for the cockpit of the spaceship from a third piece of plywood. Assemble into an "L" shape. Apply wood glue to the edges and secure with screws. Position the cockpit onto the front of the frame and secure with screws.
Paint the spaceship and then place the mattress into the center of the wood frame.