Systems for generating electric power from wind are disclosed, which use buoyant aircraft and spinnaker sails to generate very large pulling forces, which will be used to drive electric generators. The buoyant aircraft, referred to as “airbarges”, will have large, wide, and flat shapes which combine various traits of kites, manta rays, and “flying wing” aircraft. They can be flown “nose up” during the pulling stage of each power cycle, and “nose down” during retrieval. Spinnaker sails are comparable to horizontal parachutes, with tethering systems that will enable them to be pulled back to a starting location in a “luffing flag” or “closed umbrella” configuration. Because of various factors, spinnaker sails can generate much greater power output and operating efficiency than 3-blade wind turbines. “Webbing sails” made from interwoven straps also are disclosed, which can be used even in extremely high winds.