I'd really like to play the game in 3DFX mode with cockpits ON, but every time I play the cocpit is bugged (see attached - I highlighted the bug with red).

I think it may relate to differences between 'game' 2D setup and the 3DFX.

I tried to adjust NGlide to many different setups, turned the Vsync OFF, used many diferent screen resolutoions.

With Dosbox Configurator I use: Direct 3D with full screen and I also used many different window resolutions, none of them fixed the bug.

Do you know what may cause it?

Regards

Try turning off anti-aliasing in your GPUs settings.

Simple and it's working! That solved the problem, thank you!