This was in the comments:
"It's a wartime song about the soldiers who didn't die but turned into white swans and flew into the sky. It's incredibly poetic and still shared by most of us who used to live in the USSR, although now we live in different countries. Most of our parents and grandparents fought together, and yes, 20+ million people died, more if you count the Stalin camps that were concurrent with these war years. Most POW's were later imprisoned again by Stalin. This was pretty impressive, anyway."