With gas prices rising and the massive drought making ethanol a tough sell as a gas alternative, India's Tata Motors has hit on the perfect time to debut the Airpod, a small urban vehicle that, as its name suggests, runs on air. If you don't know much about how regular cars use fuel, natural gas or, alternatively, hydrogen is compressed in a pressurized tank, hence the 'pssf' sound when you unscrew the gas cap. Now think about air rifles. If you had the bad luck to grow up with an older brother obsessed with using you as a target (or...