There's actually a reason for that: Microsoft had a separate product called ESP [1] that was based on the Flight Simulator codebase that was marketed as a platf

There's actually a reason for that: Microsoft had a separate product called ESP [1] that was based on the Flight Simulator codebase that was marketed as a platform for doing industrial training simulations. Development stopped with the dissolution of ACES, the Flight Simulator team, but Lockheed acquired rights to continue to develop MS ESP, which eventually became Lockheed's Prepare3d [2]. [1] https://msdn.microsoft.com/en-us/library/cc526948.aspx https://msdn.microsoft.com/en-us/library/cc526948.aspx [2] https://en.wikipedia.org/wiki/Microsoft_Flight_Simulator#Closure_of_the_ACES_Game_Studio https://en.wikipedia.org/wiki/Microsoft_Flight_Simulator#Clo...