In the 1960s I saw an animated film. Among other projected advances, there was a large machine that obliterated everything in its path by shining a road-wide beam of light ahead of it -- presumably a "heat ray" rather than a laser -- and leaving a new road behind it. My fragmented memory has a striking scene of this machine cutting through the Amazon rainforest at night, and it says much about those times that the theme was entirely one of progress, with not a thought for the environment, wildlife, or original inhabitants of the region.
UPDATE: In my original question, I evidently conflated two old memories, the other being a facetious car with concrete wheels bouncing along a rubber highway. As the sources of the two memories seem to be different, and the car with concrete wheels has definitely been found, I am splitting this part of the question off for a separate answer. Apologies!