If you haven't seen the Strandbeasts, check them out. I saw one in person about 10 years ago, it seems that they have taken to the air since then.
"Theo Jansen is engaged in creating new forms of life: the so called strandbeests. Skeletons made from yellow plastic tube (Dutch electricity pipe) are able to walk and get their energy from the wind."
https://www.strandbeest.com/
https://www.youtube.com/watch?v=C97kMKwZ2-g