Do dragons exist?Watch
personally I think its more possible than most think. I can't see it as coincidence that thousands of years ago, hundreds of cultures that could never have met, all thought of the same creature independently, a fire breathing, magical, winged reptile... Vikings, Orientals, British, Meso-Americans and Australian aborigines.
possible evolved from early crocodiles, developed fire and flying as a means to compete with the dinosaurs and became widespread like modern wolves or cats. at the extinction that killed the dinosaurs, most dragons also died, but a few survived in remote places. maybe eventually hunted to extinction or outcompeted by early Homo sapiens?