KC-33A – A proposed 747 was also adapted as an aerial refueling tanker and was bid against the DC-10-30 during the 1970s Advanced Cargo Transport Aircraft (ACTA) program that produced the KC-10A Extender.
KC-33A – Foi un 747 proposto para actuar como avión de reabastecemento aéreo, sendo unha aposta contra o DC-10-30 no programa Advanced Cargo Transport Aircraft (ACTA) que máis tarde produciu o KC-10A Extender.