Now we're getting closer to the next official release!
I'm glad to let you know that we're going to release 2.6.0 soon. Now 2.6.0-RC1 (first release candidate package) is available for Macs. The objective of this package is to improve the quality of the official 2.6.0 release (on 17-Feb-2012). So we would like you to help us improve the quality by downloading it, using it, and sending us bug reports as well as constructive feedbacks. Please consult "ReadMe" enclosed in the dmg package and Note below before you post a bug report. Some known problems are written in that file. I hope you enjoy the bleeding edge of FlightGear.
You can download 2.6.0-RC1 package from Downloads page on this site or source forge
Note: There are two changes on the GUI Launcher and the Simulator menu. Now in-sim FlightGear menu appears on the Mac menu bar just like other Mac Apps. Another thing is that ~/.fgfs is not used anymore. it's moved to ~/Libarary/Application Support/FlightGear.
Have a wonderful flight!