Unmanned aerial system (UAS) design takes its roots from the basic aircraft design concept. This research is to study an aerodynamic design from shape optimization and fuel efficiency point of view along with incorporation of CFD for longer loiter time in search, rescue and surveillance UAS. The basic premise of subject study is to explore the existing design concept for shape optimization on a blended wing body configuration. It is an effort towards learning the design process and of fuel efficient UAV design. The design approach for unmanned aerial vehicle also would have to consider the important aspect like propulsion characteristics, airofoil geometry selection, its tail arrangement, layout, lofting, propulsion system, fuel system integration, aerodynamics and stability performance achieved.