Grumman Gulfstream IIIGulfstream custom 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 GII include a revised wing of greater span and area with drag reducing winglets, more fuel tankage and thus range, re profiled nose and a 97cm (3ft 2in) fuselage stretch. Production deliveries of the G3 began in late 1980 and continued until 1986