C-40 Clipper / USNBoeing C 40 Clipper airplane model. The Navy required a Navy Unique Fleet Essential Airlift Replacement Aircraft (the NUFEA RA Program). This aircraft, since designated the C 40A, was required to replace the aging C 9 fleet. Boeing offered the 737 700 new technology aircraft in response to the Navy's request for proposal. The Navy did not request, and Boeing did not specify any particular equipment to be designated by manufacturer and model number