BTRL ships typically go at 300ms. I have and old OpenGL and so haven't played it very much (all the ships show up as black shadows), but I did get some useful insights. One, at that kind of speed, you have to actually be worried about asteroid collisions. They will typically do 25% hull damage or so. Two, the AI is totally worthless at that speed. During the training mission my "instructor" said, "hey, watch me attack this drone". I know this wasn't "supposed' to happen, especially in a high-quality campaign like BTRL, but she chased the AI ship around in circles for an eternity. It's just way too fast for the computer at that speed.
I was planning to jack up fighter speeds to a reasonable level, say, 200m/s, for one of my campaigns. The idea is that the player is genetically modified for 10X reaction speeds, so he's actually going at 2,000m/s or .5% the speed of light, a reasonable small fighter speed. Your best bet is to make the primary weapons semi-guided. Anyone played Starlancer where you have limited auto-aiming (sometimes your cannons automatically aim if you get the reticle close to the lead indicator)? That's a good idea for high-speed combat. It makes hitting targets a helluva lot easier.
But remember that real jet dogfights take place at closure speeds in excess of 2000 kilometers per hour, they're just pretty indecisive. Most kills are scored by missiles, with gun kills being rare and considered the mark of an expert. It's doable, just challenging, and it would take away from Freespace's "blast everything" arcade feel.
