Move an AI Pawn wihtout Nav Mesh Bound Volume: implementing my own AI Controller

I’m developing an Arkanoid clone and I’m trying to figure out how to move the monsters.

I have found information about how to move AI enemies using Nav Mesh Bounds Volume but, my enemies fly, and Nav Mesh doesn’t support fly, I’m wondering if it is possible to create my own AI controller to move the enemies.

The problem is to know where the monster can move.

Who can I implement my own AI Controller?

Steering behaviors are a good substitute.
Steering behaviors: Seeking and Arriving - Projects Of Some Degree Of Interest - GameDev.net

That or you can use a package in the UE marketplace.