High Quality Content by WIKIPEDIA articles! Microsoft Flight Simulator (sometimes abbreviated as MSFS or FS) is a series of flight simulator programs for the Microsoft Windows operating system, although it was marketed as a video game. It is one of the longest-running, best-known and most comprehensive home flight simulator series. It was an early product in the Microsoft portfolio – different from its other software which was largely business-oriented – and at 25 years is the longest-running franchise, predating Windows by three years. Microsoft Flight Simulator may be the longest-running PC game series of all time. In January 2009, it was reported that Microsoft closed down the ACES Game Studio, which was responsible for the series.