The „High Altitude and Long Range Research Aircraft“ (HALO) is a research aircraft for atmospheric research and earth observation of the German science community. HALO is based on a production G550 business jet from Gulfstream Aerospace Cooperation. It has been modified in many ways to offer the technical infrastructure for very diversified scientific payload requirements.

The aircraft is operated by the Flight Experiments (FX) facility of the German Aerospace Center (DLR) in Oberpfaffenhofen, near Munich. The Special Airport of Oberpfaffenhofen (ICAO code: EDMO) is HALO’s homebase.

HALO was initially funded by the Federal Ministry of Education and Research, the Helmholtz Association and the Max Planck Society. The operational standby costs are shared by the German Research Foundation (DFG), which represents the German universities, the Max Planck Society, the German Aerospace Center, the Forschungszentrum Jülich, the Karlsruhe Institute of Technology and the Leibniz Institute for Tropospheric Research. Together, these institution form the HALO consortium. The HALO consortium partners are the main scientific users of the aircraft, but it is in principle also open to other users.