At last, the concept of 'air cars' is taking shape outside the world of the sci-fi movie. We are to have flying taxis on the horizon by 2023 we are told. This will add a new dimension to that ride home after the Saturday night party which has been such a let-down to date. What is most interesting is that a number of organisations will be collaborating on the software, hardware and energy side to make this possible and the vision is much bigger than the cars alone. This will impact on how urban mobility at large operates....