I disagree with calling it only the "Airlines of Russia" forum. Many of us who are based in this part of the world fly frequently between Russia and many of the other countries in the region, often using non-Russian airlines. I would like to ensure that AeroSvit, Air Astana, Azerbaijan Airlines, and other similar airlines are included.
And I am sure that people from other countries will have less of an issue being told "use the Airlines of Former Soviet Union (or even Airlines of the CIS) forum" than "use the Airlines of Russia forum".
As to whether CIS or "former Soviet Union" is more correct, there is no clear answer. While "CIS" is more current than "former Soviet Union", it excludes some countries and frankly the CIS is largely irrelevant to people. But it is a more accepted term in the corporate world.