This chapter reviews several hypersonic vehicle designs, primarily with the goal of illustrating how the use of hydrogen is intrinsic to the design of such vehicles and how it is accommodated and employed. The performance of a hypersonic vehicle is critically dependent on the characteristics and performance of its propulsion system. Depending on their intended application, hypersonic vehicles will employ ramjets and/or scramjets as a fundamental element of their propulsion system. The choice of the boost propulsion system for a hypersonic vehicle depends in large measure on the intended application for the vehicle. Hypersonic vehicles are often designed to use lifting surfaces to also provide precompression of air which subsequently enters inlets. Structure of a hypersonic aircraft must sustain the stresses due to temperature effects, in addition to the stresses due to mechanical loads.