In this paper, a new conceptual "Engineless CFJ Aircraft (ECA) is designed and studied by CFD analysis. This aircraft will have no conventional propulsion systems (propeller or jet engine). The new concept airplane will use the fixed wings themselves, in a flying wing configuration, with the inclusion of the newly developed high performance co-flow jet (CFJ) airfoil, to produce both lift and thrust. The energy expenditure for this aircraft will be extremely low. The energy consumption is mainly the power to pump the jet, which can be accomplished by electricity generated by a hydrogen fuel cell. No combustion is therefore needed. The maneuverability and safety of the airplane will be relatively high due to the high stall margin of the CFJ airfoil. CFD aerodynamic analysis is presented for both the two and three dimensional cases for a range of angles of attack.