Birdman,
There are a few pre WWI craft out there for download, In my hanger I have a Wright flyer, Bleriot, and a Curtiss Reims Racer that I have downloaded from various sites over the last year. they are out there mate, just have to look for them.  try using search on simvation, surclaro (http://surclaro.com/nuke/html/download.php) or fsplanet (http://www.fsplanet.com/)
best of luck finding what youre looking for
-Steve-