The Alfred Wegener Institute uses ski-equipped aircraft to support and to conduct its research activities both polar regions since 1983 and provides access to the aircraft to the German scientific community. Beside logistic support of field groups, the aircraft were utilized in glaciology, geophysics, meteorology, and physics of the atmosphere. At the beginning Dornier aircraft, first POLAR 1, a Do128, and POLAR 2, a Do228, followed by two Dornier aircraft of typ Do228 were used. While one aircraft, POLAR 3, was shot down on the ferry back home above Morocco in 1985, POLAR 4 was damaged beyond repair in 2005 by a hard landing on wheels at Rothera, Antarctic Peninsula, and replaced in 2007 by POLAR 5, a Basler BT-67, which is converted DC-3T.The instrumentation of the research aircraft is under constant development and comprises standard airborne instruments as well as systems especially designed for use in polar regions. Among the available systems are for instance various standard laser altimeter and radiation sensors but also especially for use in polar regions developed ice thickness radar systems and a towed EM-bird for measuring sea thickness. Because the polar aircraft are quite often involved in international projects, there are also third party instruments certified for use on the aircraft of the Alfred Wegener Institute, for example ESA radar altimeter ASIRAS or the methane sensor of the Geoforschungszentrum Potsdam.Since the first austral season with airborne support 1983/84 nearly more than 20 airborne missions were conducted in Antarctica and about 40 in the Arctic. While most surveys in Antarctica were flown for projects with a glaciological-geophysical focus, those in the Arctic are focused on atmospheric research. In the course of time, the aircraft are more and more involved in international collaborations, for example the CryoSat calibration and validation experiments CryoVEx with ESAs ASIRAS altimeter and laser scanner or the PAM-ARCMIP survey focused on sea ice thickness measurements and measurements of trace gases in the western Arctic region between Svalbard and Alaska. Highlights from these and other projects will be presented in the talk.