What's cooler than jetting from Paris to Tokyo in under three hours? Getting there in a biofuel burning hybrid rocketplane. The recently announced superjet, the Zehst (short for "Zero Emission Hypersonic Transportation"), loopholes around the whole pollution angle by only using its rocket engines in the stratosphere. Below the ozone however, seaweed-biofuel powered jet engines will kick in for some keen, green landings. Don't get too excited though, the EADS won't even have a prototype ready until 2020, and commercial flights aren't expected to follow until the hump of the century. Look on the bright side though, you've still got that airline-approved Galaxy Tab to keep you occupied for the next four decades of long, dark, redeyes. That's almost as cool, right?