However, balloons are at the mercy of the weather they are intended to monitor: they can travel only with the wind, rather than where meteorologists would like them to go.

ECONOMIST: Robots in the cockpit

We have doubled the distance our cars will go on a gallon of gas, and the amount of renewable energy we generate from sources like wind and solar -- with tens of thousands of good American jobs to show for it.

WHITEHOUSE: State of the Union 2013

We have doubled the distance our cars will go on a gallon of gas, and the amount of renewable energy we generate from sources like wind and solar - with tens of thousands of good American jobs to show for it.

BBC: State of the Union: Obama pledges to reignite economy