X-Plane is the ultimate flight simulator. It contains more than 40 aircrafts, from civilians to commercials, military fighters to VTOLs, and mega-planes to supersonics. You could choose from over 30,000 airports, and NAVAIDS in an entire world to fly. There are 35 systems failure you could be requested manually or randomly. You could have an unlimited add-on with the World-Maker, Plane-Maker and Part-Maker programs which is included from the CD.
 Hardware Requirements
Intel Pentium II 300 or AMD K6-2 300 Mhz
80 Mb Hard Drive
2x Cd-Rom drive
DirectX certified soundcard
8 Mb Open GL compatible video card required for 3D acceleration