I wouldn't so far as to call it imaginary Reaper. I remember that situation, I think it was about a month or two ago. The Rooks and Nits were working together to shut down the Bish. This is fine as far as I am concerned. I saw Rooks and Nits flying together at the few remaining Bish bases..
This isn't the result of any kind of alliance or real cooperation. When one country has been reduced to such a small area, it just happens that planes of both enemy countries can be encountered in the same airspace, even more so if - for whatever reason - there is no real fight on their own fronts. On this map shown in the first screenshot, it often happens after A18 has been captured by the enemy. It's a short flight from there to any of the southern country's front. I often visit the infamous A1-A19 furball area even when being in the 3rd country that doesn't have a base there. It's just a short hop over the pond for a 262 or Ta 152.
Of course in the paranoid world of many AH player, that means "they have a truce", "they gang us a s usual" and "they never fight each other", when it's really a result of map design, current distribution (and numbering!) of bases, player numbers on each side, the current state of "the war" and a few more or less subtle psychological factors.
