"Why can't you fly now, mother?"
"Because I am grown up, dearest. When people grown up they forget the way."
"Why do they forget the way?"
"Because they are no longer gay and innocent and heartless. It is only the gay and innocent and heartless who can fly."
You see, Wendy, when the first baby laughed for the first time, its laugh broke into a thousand pieces, and they all went skipping about, and that was the beginning of fairies.