[astrodust]

Engineers don't necessarily think in terms of today's equipment when writing out models that describe the problem. They think in terms of abstract concepts, like "power source" and "lift generator".

We're already trying to build a space elevator when we don't even know what material can possibly withstand those forces. It's something over the horizon, but we're hopeful we'll find it. Likewise, powered flight was possible, the only problem was finding lighter, stronger materials for the airframe and a lighter, more powerful engine to fly it.