"Airbending?" Law has no idea what the man's talking about, but he may well be from some island he's never heard of, brought here inexplicably just as Law himself was, so no wonder. "Well, good luck with that."

Since it sounded important to the old man. And since it sounds like he's some sort of teacher of that 'airbending' technique, whatever exactly it is. Not devil fruit powers, since it can be taught. Haki? Possibly, Law's heard haki can be called different things in some remote parts of the world. Or something else entirely.

"Maybe we should both ask around."

Sometimes you can learn things more quickly when you have more people.