OP if you want to save fuel you can pick up a few tips by watching
the video.Here is CAT talking about fuel usage and how to save fuel. Even "if" the wing did any good look at all the other "big" factors that go into fuel savings.
(BTW, the posters that talk about big rigs and compare them to trucks and travel trailers are trying to compare oranges and footballs. Even big rigs fight and fight and fight the wind trying to get in back of the aero before it hits the trailer even through there is very little space between the wing hood and the trailer.)