Try matching the black points and white points of the 3D image to the back ground image. Also try to do a lightwrap to the plane so that background can appears to be closing in on the edges. Bounce light and reflections from under plane of the ground can help to. Match your plane lighting to the sky light a little more also.
not sure about light wrap as it is a front lit scene. But definitely needs some more ground bounce/ambient. If this is animated then remember to add variation to the aircraft’s flight, to many times the tracking seems to lock down on the thing flying when it should be drifting in frame in all directions (including Z).
An easy way to fake the motion blur is render a head-on shot of the propeller against a white background. Then take it into Photoshop and apply some Radial Blur. Apply it to a mesh, and in the Texture settings, set the Influence:Blend setting to Multiply. The white area will disappear.
I exaggerated the right side of the pic below to show that the cylinder mesh has some thickness to it.