Hi there. When I move my mouse while flying or in the ingame map, the movement stutters a lot. When not moving the mouse, I have no problems. When I installed allmods, the problem got worse.

I already tried disabling mouse acceleration, running in windowed mode and also enabling VSync.

I went to the GOG support page for the game, the only thing it suggested that I didn't try was using OpenGL in DOSBox, as I didn't find any trace of DOSBox in this installation. I'm on a notebook with an integrated graphics card as well as a nvidia GPU. I tried using both and it didn't solve the issue.

I googled around and saw some people were using a different .exe, but I didn't find it in the installation folder.

Ok, I found the solution. The .exe filed comes with Win 98/Me compatibility mode. I created a copy of the .exe (the .exe compatibility options were greyed out for some reason) without compatibility options, and it worked!
Found this solution on the SimHQ forums.