An integrated and/or modular high-speed aircraft and method of design and manufacture. The aircraft can have a supersonic or near-sonic cruise Mach number. In one embodiment, the aircraft can include an aft body integrated with a delta wing and a rearwardly tapering fuselage to define a smooth forward-to-rear area distribution. A propulsion system, including an engine, inlet, and exhaust nozzle can be integrated into the aft body to be at least partially hidden behind the wing. In one embodiment, the entrance of the inlet can be positioned beneath the wing, and the exit of the nozzle can be positioned at or above the wing. An S-shaped inlet duct can deliver air to the aft-mounted, integrated engine. The aircraft can include aft-mounted elevators, wing-mounted elevons, and forward-mounted canards for pitch control. The construction of the aircraft can be modular to take advantage of commonalties between near-sonic and supersonic structures.