Bad Piggies Tusk ‘Til Dawn Level 5-9 can be 3-starred using a single contraption, but two runs. Build the typical plane, with the small wheel in back, top wings set on the far-right block. Place a firework on the underside of the plane. The upper star box can be reached by using the firework to climb steeply to the highest platform. The lower star box requires stalling the engines and quickly regaining speed to make the climb back to the goal.
If you have a different strategy for completing this level feel free to leave a comment below.
For the upper box, putting the normal wheel at the middle and the firework at the right of the underside of the plane works well for me.
[Remember, no matter where you place the firework, after the power of the firework ends, the plane goes out of control. So, be careful]