Features
Aurora Flight Sciences' Double Bubble D8 design concept. (NASA/Aurora Flight Sciences)

Four companies were awarded contracts to come up with five configurations on paper that met very specific operational criteria for NASA’s next commercial X-plane aircraft.

The concepts had to include enabling technologies to address goals by 2035 such as 60-80 percent reduction in fuel consumption, greater than 80 percent reduction in emissions during all flight phases, and more than 50 percent reduction in perceived noise compared to the quietest aircraft flying as of 2005.

Source