There are so many flying cars available these days it's like we live in the future. Terrafugia is the latest entry into the crowded marketplace. Their design is similar to the Aerocar, which was a model of roadable aircraft. What this means for metropolitan structure is unclear, but if these become popular there will be a spike in traffic at smaller airports. While it may seem unlikely that these vehicles will become commonplace, it's important to remember that about 85 percent of Americans live within 20 minutes of an airport. These cars can be convenient if their cost comes down and the price of fuel stays low (both are unlikely). Then we can worry about designing roads in the sky and how to keep the flying drivers off of their cell phones.