There had to be allied airmen who parachuted into Albania, Croatia, and Bosnia. Have they ever found any of the bones or anything like that??
Can't answer that, although I know some British and few Americans made it out with Tito's help after this, but in nowhere near these numbers.
There are more links to this story and Wiki has a pretty good description of what happened.
USAF Major Richard Felman was the leader of the rescued Americans trying to honor Mihailovich, but he died a few years ago. When the break up of Yugoslavia happened and the US took the other side, against the Serbs back in the 1990's, Felman gave anyone who would listen, an earful: An Open Letter To Our Troops In The Former Yugoslavia From Over 500 MlAs Saved By The Serbian People During World War II (Spring 1999)