1. Introduction --------------- The Virtual Air project intends to provide a standartized (HLA 1.3 based) framework for distributed air traffic simulation. http://virtualair.sourceforge.net The project includes the following software: 1) FlightGear HLA plug-in A HLA 1.3 interface for the FlightGear flight simulator. You may also find interesting the following software: 1) CERTI An open-source HLA RTI (Run-Time Infrastructure), licensed under GPL. http://www.cert.fr/CERTI http://savannah.nongnu.org/projects/certi 2) X-Plane HLA plug-in A HLA 1.3 interface for the X-Plane flight simulator. https://savannah.nongnu.org/projects/certi http://download.savannah.gnu.org/releases/certi/contrib $Id$