Bad Piggies Flight in the Night Bonus Level 4-IX (4-9) can be 3-starred with a single contraption. Use a helicopter as your vehicle. The helicopter can reach the star box in the extreme top-right of the level under its own power, then ride the ramp back to the finish line. Having a firework on the undercarriage, pointing left, may be worthwhile in case things go wrong during the ramp descent.
If you have a different strategy for completing this level feel free to leave a comment below.