If the Zeppelin were given an eco upgrade and brought into the 21st century, it might look something like Tiago Barros’ Passing Cloud. Created from strong yet flexible balloons, the Passing Cloud is a futuristic concept for green air transportation. The incredible zero waste, cloud-like machine is powered by the wind and lets visitors experience travel as never before: instead of staring out the window at the clouds, you are the clouds. Barros recently submitted the out-of-the-box design to the Van Alen Institute’s Life at the Speed of Rail competition, and while the Passing Cloud probably won’t win, that isn’t stopping us from imagining a sky-high trip on its sloping surface.