Gulfstream III G-1159AGulfstream G1159 airplane model. The improved Gulfstream III followed Gulfstream American's purchase of Grumman's GA lines in 1978. The Gulfstream III first flew on December 2 1979. Changes compared with the G II include a revised wing of greater span and area with drag reducing winglets, more fuel tankage and thus range, reprofiled nose and a 97cm (3ft 2in) fuselage stretch. Gulfstream IIBs are G IIs retrofitted with the G III's wing. Production