I would consider this program a google sketchup professional alternative. Its easy as google sketchup professional and has just as much capabilities like exporting/importing.
Those modellers that don't want the high learning curve as gmax then I would recommend this program to new FSX plane modellers.
Everything you create in this program can be exported to gmax in .3ds format and of course we know that gmax exports directly into FSX when setup correctly.
Usage: Basically after installation launch the program and do a 'right click' anywhere in 3d space. You will or should see all the functions and shapes that you can create. After making a 3d object like a cube or cone for example. Click your middle mouse wheel once and move mouse to pan around it.
Wings 3d latest version for windows
http://superb-west.dl.sourceforge.net/sourceforge/wings/wings-1.0-rc2.exeMain site for program support:
http://www.wings3d.com/