rigidbody vibration

Hi

I have this fast moving airplane that I move by script. It's pretty simple, I calculate where it should be and I tell the rigidbody to place it there. What's odd is that the plane vibrates like crazy. Like it moves back and forth, just a bit, but enough to make it look way too shaky.

I tried everything, kynematic off, interpolate, extrapolate, none... nothing

The code is very simple, inside the fixedUpdate:

float velocity = currentHeading.normalized * (currentVelocity+(acceleration *Time.deltaTime)); rigidbody.MovePosition(rigidbody.position+velocity);

any ideas how to stop it from vibrating? In theory, without gravity and kinematic, it should not move without me telling it to :?