This video shows you how to get the skull that is hidden in Bad Piggies Flight in the Night Level 4-33. The moustache skull is located in the first gap on the hill. Build a simple vehicle with the tnt, placing two rockets pointing left. Then simply let it roll down the hill, triggering the rockets slightly before the opening. The contraption should reverse it’s course and land in the gap.
If you have a different strategy for completing this level feel free to leave a comment below.