Offshore wind parks interact with the marine atmospheric boundary layer and can create long downstream wakes of reduced wind speed and changed turbulence. During the project X-Wakes funded by the German Federal Ministry for Economic Affairs and Climate Action (grant number 03EE3008B), 49 measurement flights were performed with the research aircraft Dornier-128 of TU Braunschweig between March 2020 and September 2021, plus additionally 7 flights with the research aircraft Cessna 406 of TU Braunschweig which were done simultaneously with both aircraft. The aircraft recorded in-situ meteorological parameters (wind vector, temperature, humidity) and sea surface properties (temperature, elevation standard deviation). During the 7 additional flights, upward and downward looking pyranometers and pyrgeometers recorded irradiance in the solar and terrestrial wavelength spectra. The flights comprise vertical soundings and straight legs upstream, downstream and above wind parks for different synoptic conditions.