SOFIA, short for Stratospheric Observatory for Infrared Astronomy,is a 2.7m telescope flying on a Boeing 747SP at altitudes of 12-14km, to detect and study mid- and far-infrared radiation that is blocked by water vapor in the earth’s atmosphere and cannot reach ground-based telescopes. It is the successor to the Kuiper Airborne Observatory (1974-1995) and currently the only access to and platform for astronomical observations in the far-infrared (30-300 microns), except for balloon-borne telescopes. Although a bilateral project (80:20) between USA (NASA/USRA) and Germany (DLR/DSI), it is open for proposals from the world-wide astronomical community at large. It addresses many astrophysical and astrochemical science questions that ESA’s successful but now extinct Herschel Observatory has left unanswered and offers observational opportunities similar to and beyond Herschel. SOFIA also has many synergies with ALMA and APEX, as well as with IRAM and other submm and radio telescopes. In my presentation, I will describe the rationale behind airborne infrared observations, the mode of SOFIA flight operations, and a glimpse of SOFIA science highlights and discoveries in its first few years of observations. I will also discuss the potential of continuing new instrumentation (2nd and 3rd generation). SOFIA normally flies out of Palmdale/California, but once a year also deploys to the Southern Hemisphere (usually to Christchurch, New Zealand), benefitting from the excellent wintertime stratospheric conditions to study the rich southern skies (including the Magellanic Clouds and the Galactic Center).