The planes are not drawn to scale. Looks like your screenshot is over South Dakota. Looking at the scale on the map those planes are around 6km apart, not considering altitude differences.

Very unlikely the same height. They could be kilometers apart. It's a 3D space.

That seems neither close nor something special. There are different flight levels, so planes can cross each other safely.

yup - it just shows how little I know about the subject... agh! - It was bit spooky looking at these, and I thought I zoomed in but by the time I took the screenshot it was way oof

Now that you know, see if you can find an airport with bad weather and check out the holding patterns they do. You'll se a half dozen planes in the same circle separated by 1,000ft vertically.

Without knowing how far you're zoomed in on the map or the altitude of the two planes, I can assure you that they're nowhere near each other.

yup - just layman (me) being scared not understanding what's going on :) - then I saw earlier what the plane did (took me a while to figure out what was this about)