Relax, LF, I've played it so I can give you an answer. This is a tough call, both have the ability to fly (Jetpack vs. Kazooie), but I'd say Banjo would win because he'd use Kazooie's dragon form to burn that little monkey to a cinder.
(Funny, Diddy and Banjo actually crossed paths with each other in Diddy Kong racing)
Sora vs. Mario