Original 1931 Ford Tri-Motor Airplane Ad Proof. This Ad Proof would have been sent to Ford by the Magazines or Papers that ran this Ad. This Ad highlights the use of the Ford Tri-Motor Planes by National Air Transport. It is in fair condition with moderate wear, blemishing and discoloration [see photos]. It is printed on newspaper style paper and is creased in middle from being folded in half and has tearing around edges. Very rare piece that will make a cool framed display item.