This document discusses the different environments and categories of transportation technology. It identifies four main transportation environments: land, air, water, and space. For each environment, it outlines the main categories of vehicles. For example, for land transportation there are stationary systems like trains and vehicular systems like cars. For air transportation, there are lighter-than-air vehicles like balloons and heavier-than-air vehicles like airplanes. The document provides definitions and examples of different transportation categories to classify various modes of transporting people and freight.