Electric , hybrid - electric , and turbo - electric distributed propulsion technologies and concepts are beginning to gain traction in the aircraft design community , as they can provide improvements in operating costs , noise , fuel consumption , and emissions compared to conventional internal combustion or Brayton - cycle powered vehicles . NASA is building multiple demonstrators and testbeds to buy down airworthiness and flight safety risks for these new technologies , including X-57 Maxwell , HEIST , Airvolt , and NEAT .