[sAuronas]

The application for it might be another form of mass(less) transit. Think about dedicated, low-lying air paths for travel between cities in the Bay Area: airBart

It's not about space ...it's about congested roads. Dedicated rail (or tubes for high speed over long distance being the exception) for mass transit is not the way to think about our improving our cities anymore. There will be a hardware - and software - solution.

[knz]

Air travel means noise and carbon emissions. There is no way it's more efficient than ground based public transportation anytime soon. I work in the aviation industry and the slightest change brings a huge amount of public outcry. Between the noise, visual pollution, and energy issues it's just not going to happen.

Bad existing public transportation doesn't mean that all public transportation will be bad.