I tried US Navy Fighters for a time, back in the early 90s. I was bugged by a few things. The worst, perhaps, was the fact that all game objects were modeled as much larger than reality, in the way they were for the predecessor sim by Brent Iverson, Chuck Yeager's Air Combat. In CYAC, this enlargement was necessary because of the 320 X 240 pixel graphics. At any kind of distance a plane would be just a pixel-sized dot. I forget if USNF worked at 640 X 480; if so, that wouldn't be much of a help for the faster jet combat.
In '92 or '93 I called Iverson to ask a few questions about CYAC. One regarded the drawn size of objects. I said I had the firm impression of at least a 4-fold increase; he said it was 8. Imagine, a 10m wingspan fighter was represented as 80m wide, easily the size of the largest jumbo jetliner! No wonder things seemed to be slowed down.
Not long after I grabbed USNF, and immediately noted the enlarged planes, ships, buildings, etc. Possibly a similar enlargement factor, but certainly 4 I think. I didn't stick with it for long, for that and other reasons.
The other CYAC brethren (LHX Attack Chopper and Su-25 something something), and the Dynamix sims (Red Baron, Aces of the Pacific and Aces Over Europe) did this enlargement thing, too. But a somewhat later title which operated at a higher screen resolution and hence surprisingly also did this object enlargement is the first Microsoft Combat Flight Simulator. The weird thing is that the enlargement was in effect while the view was from the cockpit, but for external viewpoints the objects were drawn at a smaller size (possibly true scale.) That destroyed that game for me. (CFS2 was a superior sim in this--and every--respect, and I played the hell out of it.)
Another aspect of the Brent Iverson titles which makes for 'twitchy' performance is the use of simpler, perhaps even integer-based math for speed of calculation. This is manifest in such areas as non-smooth flight modeling and jittery displays at more zoomed-in FoVs.