Stealth units can only be seen if they are in the sightrange of a unit with the Reveal Stealth trait for the certain unit type (e.g. UAV has Reveal Stealth for ground troups, but can't reveal stealth for anything else.
Right of way also doesn't change anything, the only Relationship that does is shared intelligence (automatically selected if in the same coalition), which let's you see everything.

I'm not quite sure tho if stealth aircraft on the ground still has Stealth, but I don't see a reason for it not be.

Generally Stealth also isn't realistically implemented, if something is in sightrange I should see it, it's not like Stealth makes things completely invisible. But because it wouldn't be helpful to use Stealth if they would be easily detectable it's invisible.