This book sketches key design, development, and engineering issues. To think up an airbreathing hypersonic aircraft is one thing; to design, develop, and produce it is another one. Airframe-propulsion integration plays a central role, with six integration types identified. Most demanding is that of a large aircraft with both lift and propulsion located at its lower side—an approach exemplified early by the US National Aerospace Plane. Topics treated are the flight environment, design sensitivities, fuel considerations, aerothermodynamics, scramjet propulsion, airframe-propulsion integration, structural and materials issues, and aerothermoelasticity. Persistent challenges include laminar-turbulent transition and joint modelling. Capabilities and shortcomings of experimental, computational, and in-flight simulation are considered. The second wave of mathematization—culminating in the concept of the virtual product—has fundamentally transformed flight vehicle design, enabling integrated, high-fidelity simulation across disciplines. In this book, students, design engineers, and technical managers will find ample insight and practical knowledge regarding hypersonic airbreather design.