I've released the FlightGear CVS binary package as of 2009-07-08 (r229).
The new feature on this release (for Mac OS X) is the Aircraft Preview. Thanks to fgviewer utility, it is really easy to see and tweak aircraft 3D models. You can try "Advanced Features" >> "Aircraft" >> "Preview" on the GUI launcher to preview the selected aircraft. On the preview window, you can tweak a model using keyboard and mouse. Pressing "h" key on the window will show you some brief instructions.[...]