Some thought-provoking material I discovered:
My mom was researching dinosaurs a while ago, and she came across the flying reptile Quetzalcoatlus. With a wingspan of 32 feet, they could have easily carried a human.
The Nazca Lines of Peru also pose some rather large questions. This article ends with this thought:
Movies such as Dintotopia may seem fantastic, but there is nothing to suggest that humans did not ride dinosaurs/dragons in the past.

So I'll leave you to research and answer the question: Were Dragonriders once real?

lol. I don't think with any certainty we can say that they were. But I think it's entirely plausible! I also think it's possible that these people had mechanical means of flying. *Shrug* Think of all the technology from before the flood that we don't know about!

True. But as fantasy nerds, it's neat to consider. lol