The Tanks Are Coming (1941)

The Tanks Are Coming is a 1941 American Technicolor short film. It is primarily a recruitment movie, but can also be regarded as a propaganda movie or a documentary with some light relief. Like Dive Bomber (of the same year) it is a pre-Pearl Harbor movie, made with the co-operation of the relevant branch of the US armed forces, showing off US military material to the US public, in lavish Technicolor. This material is shown in motion, both on the road and in the field; training equipment and methods are also featured.

More at Wikipedia.