Bad Piggies When Pigs Fly Level 3-36 is three starred in two steps. Obtaining the box usually occurs with Krak Snapping, so that needs to be done separately. To avoid the Krak Snap, your contraption should be four squares long with two fireworks on the second square. Hope you touch the finish line before the wall.
If you have a different strategy for completing this level feel free to leave a comment below.