The former was a cheaper derivative using the 727's existing technology and tail-mounted engine configuration, while the latter was a twin-engine aircraft which made use of new materials and improvements to propulsion technology which had become available in the civil aerospace industry.
O primeiro era un derivado máis barato usando a tecnoloxía do 727 e a configuración de motores montados na cola, mentres que o segundo era un bimotor que usaría novos materiais e melloras na tecnoloxía da propulsión que xa estaban dispoñibles na industria da aviación civil.