Very cool! I love the yellow car the most because it really conveys motion the clearest, and the little flapping adds a great touch of personality. Is it just me or does the yellow car also have the most shading and highlighting also? The red car could use a touch more motion, such as in the wheels to convey driving, and I think just a bit more shading can't hurt. I love the truck's front window and wheels, but the trailer just looks like a moving rectangle. Details definitely can't hurt there, like texturing or a logo.
I love the form and detail on the jet, but I think more highlighting and shading can create a starker appearance in the metal.