Transportation

This Swedish start-up is building an electric airliner
The mail is finally going electric (its trucks, anyway)
Rolls-Royce tests its first hydrogen-powered plane engine
This amphibious electric tricycle (and camper) costs $14,600 
The technology we (or aliens) need for long-distance interstellar travel
Stanford engineers warn that electric car charging could crash a grid powered by renewable energy 
Walking to school is more likely to keep kids active as they age
Electric planes are coming: Short-hop regional flights could be running on batteries in a few years
Paradox-free time travel is “logically” possible, say physicists
“Up to 2.4 million new apartments” legalized by bipartisan California legislation