you are totally ignoring the facts.......
if hartmann was sneaking up on someone,(which we know most his kills were done that way) how successful would he have been towing around a neon sign the size of his plane.......which looking back or around his targets would not have been able to miss.....
plain and simple.
Not plain, and not simple. Hartman got close. So close you couldn't miss, then he fired. Sometimes he was so close he aimed a single 20mm cannon round directly into a P-51's radiator scoop, and knew he had doomed the US pilot. At that range it's NOT about icons.
You "no icons" folks (and yes I'm turning it into a polarization at this point) keep using that argument but it doesn't hold water. In reality you can look somewhere and easily see the plane without an icon. In the game you can look that way and easily miss it.
You don't understand the difference between what you notice instantly with your eyes and what you can't notice very easily with an LCD.
In reality your eye is drawn to motion. Even a tiny fly is easily spotted across the room. You can spot a jetliner at 15K out in the distance without looking and without hearing it -- you just see the motion and look at what it is.
Human vision and perception is so far beyond this game that icons don't even make up for it. They can replicate some of it, but it's still not as informative as your real eyes even WITH icons.
Aces High is also an artificial fish-eye world. This helps simulate the near 180-degree peripheral vision we enjoy on a daily basis. However we can easily move our head to look a degree that way, 40 degrees up, 30 degrees this way, etc. It's fluid and instant and intuitive. In a game that doesn't work as well, not even with TIR. This artificial wide-angle view does a number of things to help the gamer us (not the real us) by reducing the F8, kp_4, kp_5, motions to track something that is instantly doable in real life.
We have had real pilots, from cessnas, to airline pilots, to real combat pilots, we've even had WW2 P-38 pilots way back (he thought the P-38 modeling was pretty good, way back in the early years), and we've had people show the physics, the math, the science of it all.
There is nothing about "no icons" that is realistic. Even WITH icons you're still at a handicap. It is filling in for major inherent flaws in trying to replicate human capability. It's not unique to AH either.