There isn't much commentary, or even an article, to go along with this illustration, but perhaps the image speaks for itself. Seven million years ago, the first birds took flight, and since then, they've been evolving to become better at it. In the same way, the early airplanes would take off clumsily, wobble mid-air, and crash a few times until we perfected the technology. Finally, we pointed out how closely the silhouette of our first airplanes resembled those of early bird-like creatures.
Read the full story in "The First Successful Fliers of Man and Nature"