Aircraft appear as uniform bold specks across a variety of distances...

[Redroach]

Originally Posted by PissyChrissy

This makes it unrealistically easy to spot distant aircraft, and it makes it impossible to judge the distance of aircraft between 3km and 9km.

Yeah, this is the problem which CoD faces, besides its real bugs and issues.

Did you actually fly an aircraft and tried to spot one-engine planes at greater distances IRL? But the 'unrealistic' argument stands firm, right?
I've read quite a few stories about pilots spotting bogeys at distances greater than 10km. So, what's the issue again? The screenshot looks perfectly reasonable to me. RL pilots have a way better resolution than we do on our pixel screens. Plus there is still the single biggest advantage in RL: Stereoscopic vision.I'm 100% certain that our view is (still) worse than those of real pilots.
And as to juding different distances... well, I see differently-sized spots on your screenshot (which is probably down-sized), the size of them corresponding quite accuratly with your range labels.
Additionally, a bigger spot near a smaller spot could be an 109 at 7km and one at 9km - or it could be an 109 and a He111 travelling alongside at 9km.
Judging distances is an advanced feature that should take a while to get used to. And you can alwas switch back to markers.