can someone explain the difference between the aircraft.cfg file and the *.air file because thay both seem to be pretty much the same.also are there tutorials anywhere that help one understand the *.air file?

In lay terms, the .air file is the flight dynamics program. It also contains tables and parameters from which all the dynamics computations are driven. The .cfg file is a simple external way to provide inputs or tweaks to the .air file.There are many more parameters and tables/arrays of performance/response data in the .air file that most of us can not handle.As FS evolves, so do these two files. MOre 'external' parameter inputs are now allowed. The confusing part is now which file parameter overrides the other.MS has also chosen to provide more 'effectiveness' inputs so that we can influence changes without really having to understand the data details and relationships.There are several .air file editors available. My personal choice is AirEd. These programs allow you to edit the specific data parameters and tables.With a lot of patience and common sense, one can sort out the 10-15 key sections, begin to understand basic relationships and do some nice things. However, the complexities of the inter-relationships should sometimes be left to the hard-core.You can get AirEd here: http://members.dsl-only.net/~eagle/Milton