Airborne observations of sea-ice plus snow thickness were made in August and September during POLARSTERN campaign ARK-XXVI/3 (TransArc) in the Arctic Ocean. The data record consists of 16 surveys in ice-covered part of the Arctic Ocean along the cruise track. For each helicopter survey, the geolocated thickness data from an airborne EM sensor is provided with a point spacing of approximately 4 meters. The thickness values of the EM-Bird include the snow layer, when snow is present on sea ice. Each thickness values represents the average thickness within an area of approximately 50 meters. Larger gaps in the thickness information are caused by regular high-altitude calibrations of the EM sensor. The data is routinely used to assess changes of the sea ice thickness trends in the Arctic Ocean and for sea-ice process studies that include the sea-ice thickness distribution.