Beware the giant McDonald's food flying off the restaurant chain's delivery trucks! That's right—french fries and Big Macs appear to be struggling against the wind in a new "moving billboard" campaign on delivery-truck sides. The backs of the trucks also have messages for drivers. "Whip through traffic," says one, showing McCafé shakes. Another (image after the jump) shows a container of fries and the message, "No passing." Honk! Honk! Oops, we're holding up traffic!