drag: YES, see https://observablehq.com/@pstuffa/faux-3d-globe

here's a (very incomplete) plugin to show how to add marker-start and marker-end properties to the arrows https://observablehq.com/d/6ebe949dcd044774

Thanks...I'll study it!

Any idea how not to let the arrows disappear when rotating?

I think you want a completely different approach: rather than planar arrows between two projected points, you just want a geo feature which looks like an arrow?

I've implemented a basic geometry below; but it doesn't look like an arrow at all… there's a bit more work to do…

Aaaah, yes exactly that...! Now getting the arrows would be nice...logically in my head it is simple: from the end point depart in the back direction +x degrees for y length, do the same for -x ;-) I will see whether I can put something up...OR if I can survive without arrows ;-)))