A multiplayer-oriented WW2 flight sim similar to Aces High, Air Warrior and Warbirds series. As the official server is no more, you still can play with bots as it seems.
Info (older 3.5 version)
http://www.mobygames.com/game/windows/fighter-ace-35
link (torrent, actually)
http://www.moddb.com/games/fighter-ace- ... inside-zip