There's nothing Chikusa can really say right now- partially because he's trying not to choke on all the rainbow hair that Celestia has no shortage of. Instead, as everyone tries to plan things as they take to the skies, he keeps his line hand ready and the other holding onto Celestia.

If anything suddenly comes at them, he'll be prepared to toss up a defensive borderline. It's the best he can do while in midair.