A Civilization advance.
Sustained, self-powered motion through the air, or flight, has tantalized humans since the dawn of time. Just after the turn of the twentieth century, Orville and Wilbur Wright made the first four controlled, sustained human flights at Kitty Hawk, NC. The technology of flight advanced rapidly, and within a relatively few years, aircraft were circling the globe, safely delivering passengers and mail at record speeds.
Prerequisites: Combustion and Physics
Allows for: Advanced Flight