We got DS a car mat at spotlight, he loves it.
We decided not to do the stickers but we got a set of four small canvases instead - car, plane, bus and boat.
Kmart have transport themed doona covers (pretty sure spotlight have them too)
DS also has truck bookends and a few wooden cars and trucks in his room. It's a popular theme so you shouldn't have too much trouble finding what you need! Good luck, I love doing up kids rooms!