ok, does anyone know how these traits work? invisible, flag unit, hidden nationality, and stealth? Do people use these traits in their mod's? I assume hidden and stealth probably refers to the stealth bombers/fighters, can these be used for normal units?
Thanks,
m1

The "Help" button in the lower right corner of the Units tab is actually helpful :)

"Invisible" means just that -- any unit so flagged can only be seen by units with the "Detect Invisible" attribute; this is mostly used for subs, but other uses do suggest themselves (special ops; ninjas; etc.)

"Hidden Nationality" means a unit can be seen (unless, of course, it's also flagged "invisible") so that an attack using such a unit cannot be traced to its owner -- i.e., such an attack cannot count as a declaration of war. Think terrorism etc.

The "stealth" ability is for aircraft and greatly reduces their chances of being intercepted (IIRC the default settings are 40% chance of intercept for non-stealth and 5% for stealth).

Hope that helps --

Oz