A data reduction technique applicable to constant-temperature hot-film and hot-wire probes is presented which is used to determine flow angle and mass flow rate in an unknown flowfield over a wide range of flow conditions at supersonic and hypersonic velocities. The technique virtually eliminates the effect of Reynolds number on a probe's flow angle sensitivity. Methods for extrapolating a limited amount of mass flow rate calibration data to include the range of mass flow rate encountered in an experiment are also given. This technique has been applied to data obtained using a hot-film probe during surveys in the leeside flowfield of a Space Shuttle Orbiter configuration.