But here's the thing, flight is not a fighting style. Swordsmanship is and Zoro can use fast and power range attacks.
Besides, Kaido can fly and he's facing people who can't.
Besides, Kaido can fly and he's facing people who can't.
If his his combat style revolves around moving fast in the air and his fire kicks as seen in the anime then you could easily say his combat style matches Sanji moreso than Zoro.
Kaido is a relatively slow moving flier who prefers to act as a giant target in full transformation, within jumping distance because he's a dumbass, and none of the scabbards are going to get very far against him. If his hybrid can fly I don't see non fliers even being able to actively engage him, hence why you need Luffy who can either rocket jump way farther than any other non flier or with access to G4 that can fly very fast (or Law/Kid who have teleportation/flight)