The correct answer is “the flying machines.”
The project that helped establish Leonardo’s reputation as a creative and talented engineer was “the flying machines.”
Da Vinci always liked the idea of man flying. That is why he applied his engineering knowledge into developing a flying machine he named the “Onrnithopter.” Of course, he was inspired by the big birds that extended their long wings. The flying machine that he invented hat a wingspan of 33 feet. The frame was made of pine and was covered in raw silk. So it is true that The project that helped establish Leonardo’s reputation as a creative and talented engineer was “the flying machines.”