i''m going to call a "partial b.s." on that. no doubt familiarity is key but unless you have an insanely superhuman ability to judge distance or you fly around with a military grade range finder, i could see a mile to mile and a half, but not 2 miles or beyond. even then determining a cessna 150 from a 206 at that range is not something that can be done without aide unless you were at such an angle as to be able to clearly see the landing gear and cabin area, not to mention being highly familiar with the aircraft. most of us don't have the aircraft familiarity experience let alone the flight time, but i've done the 1 mile and 1.5 mile veiwing of various aircraft with and without range finders, the obvious ones are easy but the similar types were more difficult and i can only imagine trying to properly identify single engine fighters a mile or more away that weren't painted bright white from inside a scratched and dirty canopy with the sun glaring down on you.
I'm going to give you some advice a 3D animation instructor once gave me.
Pay attention to the world around you, right now, right here. When you're walking, driving, or sitting, keep your eyes open and observe things.
I think your entire clinging grip on the belief that "no icons" is realistic is based on a false understanding of distances and human sight. I have a stretch of road I drive along to and from work daily. There's a hill at each end of this stretch and a long dip in between, meaning you can look up and see the road for at least 2-3 miles (if not 5 or more) and clearly pick out lanes, trees on the side of the road, see how much traffic (cars, trucks, etc) are on the road.
I see aircraft small and large flying over downtown here where I work. There are certain minimum altitude regulations here so I know they're at least a certain distance away, but yet you can still make out plenty of details. You can see the livery colors of airlines at least 10000 ft AGL clear as day. You can make out individual details on helicopters and cessna-type planes. I may not be able to ID the plane if I don't know the names, but if I look at it I can describe clear as day "low wing, twin engine, engines forward to the tip of the nose, long fuselage, round, high flying tail, etc"
I don't think you really understand the distances you see every day nor the details you are observing, and so you cling to this no-icons ideal. You're able to see quite a long distance and pick out many details.
So I again encourage you to look at the world around you and stop and actually think about what you're observing more. You may come to realize just how wrong you've been.
