How do u find enemies online..?

[whoarmongar]

To be honest my bigest problem with spotting enemies is this.
At long range its easy a dark black spot in the distance, so you close the range and at some point that black spot just disappears and I cant see them anymore until suddenly they reappear again once more much closer.
Perhaps its me, my PC or my monitor but its just so counter intuitive and damn frustrating.
A closer aircraft must be more visible than one far away.