Airbus's Airseas subsidiary is working on a kite system that can reduce fuel consumption by a claimed 20%: https://www.airseas.com/ https://www.airseas.com/ Se

Airbus's Airseas subsidiary is working on a kite system that can reduce fuel consumption by a claimed 20%: https://www.airseas.com/ https://www.airseas.com/ Seems like a kite + battery combination could be quite effective.