Abstract: Systems and methods capable for use in the development of high-speed, shape-transitioning, inward-turning inlets for air-breathing hypersonic vehicles, and inlets formed thereby. The systems and methods preferably provide for designing high-speed inlets for air-breathing hypersonic vehicles, wherein unique solutions are defined in each osculating plane of the inlet. Such systems and methods optionally provide an optimization process for tuning the post throat-shock Mach number of the inlet, and/or designs a shock-capture surface using a parallel-streamlines methodology, and/or a double cowl-lip geometry to allow flow to spill overboard.