SKY RIDERS (1976, USA/Greece, 91m, PG) *** Action, Adventure dist. Twentieth Century Fox (USA), Fox-Rank (UK); pr co. Twentieth Century Fox; d. Douglas Hickox; w. Jack DeWitt, Stanley Mann, Garry Michael White (based on a story by Hall T. Sprague and Bill McGaw); pr. Terry Morse Jr.; ph. Jim Freeman, Greg MacGillivray, Ousama Rawi (DeLuxe…