Cinematic Motion Blur of background when Camera is following a moving object.

I am working on a Cinematic project and I have created a shot where an aircraft is flying quickly over a landscape and the camera is above tracking with the aircraft. I need to create an effect where the landscape is blurred due to it’s movement relative to the camera, but the aircraft has almost no blur at all since it is moving slowly with respect to the camera.

The post process motion blur fails to do this as I get a sharp landscape and a blurred aircraft.

My research on this keeps turning up Radial Motion Blur, which appears to be a material based effect. I don’t think is the solution as my landscape is huge and has numerous large objects.