In July 2013 Johnson’s team and the US Navy successfully completed the first arrested landing of the X-47B Unmanned Combat Air System on the deck of the USS George H.W. Bush.
Managing unmanned air power
Carl Johnson, vice president, program manager N-UCAS, Northrop Grumman discusses the role of program management in successfully developing unmanned systems.

Comment: Hybridisation is a new era for aerospace
Regeneration during braking would be a good start. Some wind-milling during decent could possibly contribute. Also the engines could be lower-powered...