It would literally be like a large Eagle vs. somebodies pet lizard with wings. Completely different tiers, sizes, everything.
How would Smaug even fight back? You do realize that Rodan was literally running circles,and making laps around F-22's and F-35's, as in he was able to casually toy with multiple objects going Mach 2. As well as close to bullet time reaction speed (reacts to ejection seat and pilot shooting toward him , which is 800mph, while they were already going Mach 2+)
Plus, Rodan weighs over 32,000 tons. Smaug weighs....I don't know . Gonna check. Far far less.
He gets eaten like a little lizard.