The BACSAM II aircraft campaign, conducted with the polar research aircraft Polar 6 and the towed body T-Bird, took place from 3 April to 2 May 2024. It was based in Longyearbyen, Svalbard. In total, 11 low-level research flights and two transit flights were conducted, covering the region around Svalbard and north of Greenland. T-Bird data are available for 5 low-level research flights.The data sets present the high-frequency meteorological observations from the T-Bird towed about 70 m below the Polar 6, consisting of 100 Hz wind components (u, v, and w) derived from the five-hole-probe, as well as temperature and pressure. The wind measurements are considered reliable only during straight flight segments and are not recommended for use during aircraft turns. In addition, the data sets provide GPS position and ground speed, together with pitch and roll angles and true airspeed.