Hierarchy in air travel: Few large and many small

Here, we document the diversity of commercial aircraft models and bodies in use during the past five decades. Special emphasis is on the models that have moved humanity across the globe during the past three decades. The first objective is to show that the apparent diversity is in fact underpinned (sustained) by organization, which is a distinct hierarchy of "few large and many small" coexisting and moving people harmoniously everywhere. The second objective is to rely on the emerging hierarchy in order to predict for the future how few the even bigger models will be and how more numerous the even smaller models (e.g., drones for package delivery) will be, naturally.