Baseline (Widescreen) Solution & Issues
In the main WarBirds folder there is a file named gfx9set.cfg. Open this with notepad; it has one line of text.
The 2nd, 3rd, and 4th numbers are the horizontal and vertical rez and the refresh rate, respectively.
e.g. 0 1440 900 32 75 1 0 0 1
is suitable for a Viewsonic va1912wb monitor. Oddly, despite the fact that this monitor runs at 60hz refresh, '75' is needed; the appropriate number, 60, cause WarBirds to crash upon launching. Your monitor may or may not need an altered refresh rate figure.
WarBirds has 3 fixed fields of view (60, 75, and 90 degrees) which are available in 4:3 or widescreen resolution.
Ultra/Super-Wide (21:9/32:9) Specific Solution & Issues
Eyefinity / Surround Specific Solution & Issues
4k UHD Specific Solution & Issues