Is air attacker better or fire attacker?

It depends on personal preference and also what you're doing at the time (fire is focused on hitting multiple enemies for building damage and spreading damage, air is focused on major damage to a single target, and then even MORE damage to one target.)

Examples: Our main team is Air attacker, our secondary team is fire, my battle board teams have 2 fires, and for sb event and for some of the lost grove cave bosses I use fire+air, for Vierna in DotF air

Okay, thanks!