This paper describes the calibration process of cone-shaped four-hole pressure probes to be used for wind estimation based on airborne sensing with small unmanned aerial vehicles (UAVs). Due to the limited payload capacity and system resources of small UAVs, the probes do only have four holes in contrast to conventional five-hole probes. The probes are calibrated solely and together with the aircraft in a wind tunnel to cover retroactive effects originating from the flow field around the airframe. A lifting line model is set up to accompany this approach and to correct test section blockage. The calibration is approximated by polynomial functions of fifth and fourth order for main and cross sensitivities, respectively. The fitting results show a satisfactory representation of the probes’ behavior within the calibrated range of flow angles, that covers the expected flight envelope very well. As a result, four-hole probes can be called applicable for the task of flow angle measurement at small UAVs.