That's 340m/s, a.k.a. Mach 1. 450m/s is with afterburner. And yes, it'll be a typical speed for fighters. With minor differences, besides afterburner performance variety and acceleration/decceleration speed. I know it's a bit slow, compared to what modern fightercraft can reach ( Mach 2 and so on ), but it's the highest speed without making it impossible to play or frustrating.
I got atmosphere to work with various somewhat-hackish solutions. Rather complicated to explain, yet simple, IMO, to produce. I might release a demo of some sort, once the modpack is done, to show how everything works and improve it. And then afterwards work on the campaigns.