Grumman Gulfstream III G3Gulfstream III 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