WRLD and Udacity Create 3D Simulator for Flying and Autonomous Cars

Looking at WRLD it appears to have some fairly accurate cities - the pictures of London looked fairly accurate - but only saw a couple.

WRLD is a 3D model of the world based on a real world coordinate system, including building heights. The platform has a good chunk of the world mapped but continues to add new areas based on customers. Boston is included!

As far as cars are concerned, above ~30km/h, the noise produced by air resistance is louder than the tire noise. Cars, however, are on the ground, i.e., surrounded by massive sonic breakers (i.e., buildings). It should be quite difficult to have a large amount of flying vehicles without an enormous noise impact, unless they're flying very high.