To show the feasibility of high-speed aircrafts, one needs to have reliable performance indicators and figures of merit. As high-speed vehicles only make sense on long-haul routes, various trajectories and related optimizations were evaluated, covering classical transatlantic routes up to antipodal flights from Europe to Australia. The latter is actually the reference mission for the EC-funded projects LAPCAT I and II [1, 2] enabling the potential reduction of antipodal flight times to about 4 hours without stopover. As these trajectories are different to classical routes, due to the imposed constraints of over-land flights due to sonic boom, the necessary information on range extension is then used in the as well EC co-funded project HIKARI [3]. This enabled a more reliable dataset for a market analysis carried out by AIRBUS but is not part of study presented in this paper. The trajectory simulations and optimizations presented here are performed for the Mach 8 LAPCAT-MR2 hypersonic cruiser concept, given the GTOW and the amount of fuel on-board. This evaluation is based upon detailed aerodynamic and propulsion databases which on their turn are composed from experiments and numerical simulations.status: publishe