Please visit the following link for more information:
http://www.flightgear.org/tours/sky-diving-visualization/

Creare, Inc., an R+D research firm in Hanover, NH, under funding from the
US Army, developed a Computation Fluid Dynamics toolkit for analyzing jumpers
and their equipment, and model the resulting configurations in FlightGear.

Make sure you specify  an initial altitude otherwise you will just be sitting
at the end of the runway working on your tan.

Start FlightGear and select either:
  --aircraft=Parachutist-Scenario1 --altitude=10000
or
  --aircraft=Parachutist-Scenario2 --altitude=10000

Press F1 and F2 to toggle the two available dialog boxes on/off.

You can manipulate the joint poses individually or select from a set of
pre-defined poses, or select “Joystick” control and fly with a joystick
(or keyboard or mouse) similar to flying a helicopter or airplane.


Credits
-------------
* Dietz, A. J., Kaszeta, R. W., Cameron, B., Micka, D. J., Deserranno, D. and
  Craley, J.”A CFD Toolkit for Modeling Parachutists in Freefall”, presented at
  the 21st AIAA Decelerators Conference in Dublin, Ireland, 23-26 May 2011.
  Paper AIAA 2011-2589.

* The Creare Freefalling Parachutist model was developed by Anthony Dietz
  (Principal Investigator), Richard Kaszeta , Benjamin Cameron, Daniel Micka,
  and Dimitri Deserranno of Creare, Inc., as part of an SBIR Phase II project
  sponsored by the U.S. Army RDECOM Acquisition Center under Contract No.
  W91CRB-08-C-0135. Additional contributions we made by Curt Olson and
  Jon S. Berndt as consultants. The resulting parachutist model is unvalidated
  and therefore, should not be used other than for demonstration purposes. Any
  opinions, findings and conclusions or recommendations expressed in this
  material are those of the authors and do not necessarily reflect the views of
  the US Army RDECOM Acquisition Center.  Due to the significant contributions
  made to the project by several open source developers,  Creare has released a
  version of the resulting parachutist model to the open source community for
  continued development and use.  The FFTK itself continues development as a
  proprietary Creare project. For information on the FFTK itself, please
  contact Richard Kaszeta at rwk@creare.com, or 603-643-3800.

* Flightgear modeling, animation, and scripting – Curtis L. Olson