Here's a little something I figured out so as to not have spare parts lying around after building alt mode: Step 19: Do not use the blue piece as described. Step 20: Only use 2 of the red blocks, on the outer most positions. Leave the inner area open. Step 21: Before placing the red "wings" on top, place the head (detached from the peg) as seen in the second attached image. Place the peg piece for the head in front of it right behind the windshield standing upright. Now when you place the "wing" pieces on top, tilt the figure back a bit so the ball of the head peg leans back and clears the two "wing" pieces. Now the "wings" will fit on properly and the 2 red slanted pieces in step 22 will also fit on top properly. You should end up with two red pieces from step 20, along with two gray hinge pieces and the blue piece from step 19. Place them on the bottom of alt mode as shown in the first attached image. The final image shows that it all fits together very well without showing that there are bits crammed into the cab area.