Bad Piggies Flight in the Night Level 4-8 is three starred using two contraptions. To grab the star box requires wrecking the vehicle, so load up with rockets to blast around the loop-the-loop. To avoid Krak-Snap, drop a few of the rockets and travel slowly through the gap in the ground. Having a rocket facing the opposite direction to slow down.
If you have a different strategy for completing this level feel free to leave a comment below.
I use the first contraption in the video but two runs. To avoid krak-snap i click on one blue rocket. In mobile devices too can tap on one blue rocket or another object.