Flying AI Is Like The People On The Bus: Goes Up and Down... Up and Down

Hello all you super awesome Unreal developers, I am officially requesting some help and would sincerely appreciate any help/advice/documents/tutorials, anything that could help me in my quest for proper flying AI.

I have an airplane (a number of static mesh pieces, with the fuselage as the scene root, cockpit glass, mid wings, rear wings and propeller as children. I also have a FloatingMovementComponent to be controlled by the Navigational Agent. The plane components are built to scale.

I have a test map, it is flat landscape with tall walls (between 4k and 6k units (I believe are cm) that act as sort of corridors for the plane to fly through. I have a box collider set up as checkpoints, and I pick a random point in that checkpoint, instantiate an empty actor there, and use the MoveTo blueprint node to move there.

I have entered a custom Navigation System Supported Agent (project settings) called Plane. It has the correct Nav Agent Radius and Height (800 and 400 respectively).

I have changed the Navigation Mesh (project settings) to use 10,000 as the vertical deviation from ground compensation.

I am using the [only] supported agent among all the pieces of navigation (the movement component, ai controller, and the BehaviorTreeTask (the MoveToActor).

The checkpoints are anywhere between 3 and 6k off the ground. I have nine of them. As the plane flies to each checkpoint, it goes up and down, fairly erratically, to where it’s just hovering over the floor.

I have changed so many settings over the few days I’ve been trying to get a more smooth and elegant flight, but just can’t seem to get it.

I am more than happy to work with anyone by supplying any images, code (blueprints), setup. Please help me if you have the time.