This data set consists of the airborne measurements obtained in the framework of the AWI-campaign "SpringTime Atmospheric Boundary Layer Experiment" (STABLE) that are used as supplement for the study by Michaelis et al. (2020). The measurements were performed in the atmospheric boundary layer near three different leads in the Arctic Marginal Sea Ice Zone north and northwest of Svalbard on 10, 25 and 26 March 2013. All cases represent conditions of a nearly lead-perpendicular convective flow over the leads.For each of the three cases, different flight legs are provided (see filenames):(a) 'upwind': a vertical profile performed upwind of the lead(b) 'cross-lead': a low-level horizontal flight leg performed across the lead along the mean wind direction(c) 'lead-parallel': lead-parallel flight legs performed at different distances to the upwind lead edge at different altitudes, either above the lead or further downwind(d) 'saw-tooth': a saw-tooth flight pattern performed across the lead along the mean wind direction (only for 25 March)(e) 'lead-parallel_avg-val_fluxes': flight-leg-averaged values of mean atmospheric quantities and turbulent fluxes for the lead-parallel legsThe measurements of wind, temperature, pressure and humidity were performed with instruments mounted on a 3m long nose-boom of the research aircraft Polar 5 (see also Tetzlaff et al., 2015). For the three wind components, temperature, and pressure, the sampling rate is 100Hz so that with the observed ground speed of the aircraft of 40 to 75 ms-1 a spatial resolution of approximately 0.4 to 0.75m was obtained (Tetzlaff et al., 2015, Michaelis et al., 2020). The three wind components and air pressure were measured using a five hole probe. Air temperature was measured with a PT-100 resistance thermometer. Relative air humidity was measured with a dew point mirror. Global Position System (GPS) and Inertial Navigation System (INS) were used to derive height and position of the aircraft. In addition, a KT-19 radiation thermometer and an infrared (IR) scanner were used to measure surface temperatures. All data is adjusted to the time measured at the nose-boom.The turbulent fluxes were calculated using the eddy covariance method for all lead-parallel flight legs (see Tetzlaff et al., 2015, Michaelis et al., 2020). Mean values averaged over an entire flight leg and the corresponding statistical error are provided for air temperature, air density, horizontal wind speed, the sensible heat flux, the absolute value of the total vertical flux of horizontal momentum, and for the x- and y-components of the latter quantity.A more detailed description on the measurement techniques and flight patterns is provided by Tetzlaff et al. (2015). For more details on the post-processing of the raw data and on measurement accuracy, see Hartmann et al. (2018).