Ancient Egypt
Archaeologist here. There’s a really interesting ancient Egyptian story called the Shipwrecked Sailor in which a man has washed ashore on a beautiful island and is apprehended briefly by an enormous serpent. In the story, the serpent tells him that there used to be hundreds of others like him, but a falling star wiped them all out.
I think it’s unlikely that the Egyptians had knowledge of dinosaurs, but there’s a site called Wadi Hitan that has thousands of ancient whale skeletons from the Eocene. I think it’s possible they could have seen these skeletons and mistaken them for giant snakes. Herodotus actually tells similar tales of giant flying snakes in Egypt, and I suppose if you saw these skeletons but no trails, you might think they were capable of flight.