These aircraft have no resemblance to the original aircraft. The inspections and modifications have kept them up to date. I flew 2000 hours in the KC135 prior to 1970, and have seen the current aircraft. The engines have changed from water injection to modern fan turbines. The avionics has been upgraded to some of the most modern equipment in the world. Our sextants have finally been replaced. The worst problem the aircraft has is fuel consumption.