For instance, from the air you can see the sand dunes of the south west, and see they extend quite a ways, but you can't always see what is happening to the lands.
You also can't see some of the humorous, and sad, aspects of road travel when in an airplane overhead. One such example is signage.
And you definitely can't meet the people, and sample the cultures of the various geographic and cultural areas of the country. So, in my opinion, road trips "win."