The Institute of Atmospheric Physics develops, modifies and optimizes in-situ instrumentation for the airborne measurements of a series of trace gases. The instruments are deployed on different aircraft (HALO, DLR Falcon, Geophysica-M55, Lufthansa A340-600). Currently, the institute performs measurements of short- and long-lived greenhouse gases (O3, CO2, CH4), reactive nitrogen compounds (NO, NO2, HONO, HNO3, NOy), tracers for polluted (CO) and stratospheric air masses (HCl, ClONO2), as well as of aerosol precursor gases (SO2). For the measurement of NO, a two-channel chemiluminescence detector is used and in combination with different reduction converters, also NO2 and higher oxidized nitrogen compounds can be measured. The sensitive and versatile Chemical Ionization Mass Spectrometry (CIMS technique) is currently deployed for the measurement of HNO2, HNO3, HCl, ClONO2 und SO2. CO2 and CH4 are detected using cavity ring-down spectroscopy, O3 and CO is measured via UV absorption and vacuum UV resonance fluorescence, respectively. For the investigation of transport and mixing processes in the atmosphere, air masses can be tagged with inert tracers (perfluorocarbons) and followed in so called Lagrangian experiments over a time period of up to three days.