1.1 - The mission of IVAO ( The International Virtual Aviation Organization ) is to provide an environment for a realistic Flight and Air Traffic Control simulation via internet, utilizing IVAN ( International Virtual Aviation Network ) without charging money and available for everyone.
AVSIM offers a multitude of flight sim related information, product information/evalutions, and an abundance of downloadable share and free ware...
VATSIM is the virtual air traffic network which provides flight sim enthusiasts with virtual, online, real-time air traffic control through it's divisions world wide.