How Avatar: The Way of Water made riding an alien creature as real as possible

In an interview with National Geographic, James Cameron broke down another technological invention he and his team created to flesh out the world of "Avatar." In this case, Cameron and co. kitbashed the giant alien sea creatures by combining a Flyboard, a submarine and an honest-to-god Harrier jet. Cameron said:

"[We built machines] that could do what the creatures [in "The Way of the Water"] did: run underwater at great speed, get out of the water, fly over the surface of water, get back in the water...and we figured out how you'd really get such a thing up...like a Harrier jet meets a submarine. We built it. I don't know if you know it. 've seen at beach resorts, these things where guys go 25 feet in the air. We're using this jet engine technology to basically make a Harrier jet that had a pilot in it, and somebody could ride on it and fly above the surface of the water, dive into the water...dangerous as hell...but we figured out how you would really ride such an animal and how you would wield a [weapon] We went out and put all this information together, and we got this whole photograph of reference, brought it back to our shooting environment, taught the actors how to do it, and put it all together."

Cameron also added that his team had developed "computational fluid dynamics simulations" that allowed reference images to appear real for Na'vi physiology. It's best to take Cameron at his word here, as it looks like he brought science fiction to the real world and any further explanation would make it less and less plausible.