FlightGear development started with an online proposal in 1996, using custom 3D graphics code. Development of an OpenGL based version was spearheaded by Curtis Olson starting in 1997. Many people have contributed to the project in the years since its inception.
FlightGear incorporated other open-source resources, including the LaRCsim flight model from NASA, and freely available elevation data. The first working binaries, using OpenGL for 3D graphic code, came out in 1997. Enthusiastic development of newer versions for several years resulted in progressively more stable and advanced versions. By 2001, the team was releasing new beta versions regularly, and by 2005, the maturity of software lead to more widespread reviews, and increased popularity. 2007 marked a formal transition out of beta development with the release of version 1.0.0, ten years after FlightGear's first release in 1997.
In 2008, version 1.9.0 of FlightGear included a major change from PLIB to OSG, which caused the temporarily loss of some features like 3D clouds and shadows, while newly added features, such as particles, imparted another degree of realism to the simulation.
The FlightGear project was conceived on April 8, 1996 by David Murr who proposed a new flight simulator to be developed by volunteers. Part of the initial goals were to develop 2D and 3D graphics routines for the simulator. However this was a huge task that came to an unfinished halt at the start of 1997 as the main developer, Eric Korpela, was finishing his thesis.
Development of an OpenGL based version was spearheaded by Curtis Olsen starting in 1997, after the initial start in 1996. A large community response lead to many contributing to the project from its start in late '90s up to the present.
"I was working at the University of Minnesota at the time, and had access to Sun and SGI graphical work stations which offered OpenGL for 3d graphics. OpenGl was just starting to become available on PC hardware with things like the 3dfx voodoo card. Somewhere at this point it occurred to me that a far better path would be to leverage an existing multi-platform 3d graphics system (like OpenGL) to build our flight simulator upon.
So I proceeded to rough together a basic scenery system, pasted on the larcsim flight model, and in a relatively short time was able to show actual flight over real 3d terrain. Good, realistic 3d terrain was something the other existing flight sims at the time were pretty far behind on ... and I think my work was enough of a breakthrough that it got a lot of people excited about the possibilities."~Curt Olson 
Rather than start entirely from scratch, FlightGear developers made use of the LaRCsim flight model from NASA, with OpenGL for 3D graphic code, and freely available elevation data. First working binaries came out in 1997, with an intense updating of newer versions for several years resulting in progressively more stable and advanced programs.
Versions 0.7–0.9 (2001–2003)
By 2001, the team was releasing new beta versions regularly (0.7.x, 0.8.0, over 2001-2003) and with 0.9.xx (2003-2006). Later in the decade, the rate of final public releases slowed, but had larger amounts of content (0.9.10, 1.0.0 etc.). The maturity of software by 2005 lead to more widespread reviews, and increased popularity.
Version 0.9.0-0.9.11 (2002-2007)
The use of version numbers slowed dramatically after the late 2002 release of version 0.9.0. Versions 0.9.9 (2005) and 0.9.10 (2006) had about 8 all-new or redone aircraft adding to a total of 70-90 aircraft. Nasal was also integrated into FlightGear in version 0.9.4. FlightGear 0.9.10 won Softpedia's "Pick" award (5 out of 5 stars) on June 3, 2006 as well as the "100% CLEAN" Softpedia award.
Behind the scenes there was a 0.9.11-pre1 released in 2007 that ended up being superseded by FlightGear 1.0. The pre-version had about 33 new or redone aircraft.
Version 1.0 (2008)
The version number marked a formal transition out of beta development since the software's first release in 1997, ten years prior.
Version 1.9.0 (2008)
At the time version 1.9.0 was released FlightGear switched from PLIB to OSG, which caused the temporary loss of some of the features like 3D clouds and shadows. On the contrary new features such as particles add another degree of realism to the simulation. Most aircraft developed for OSG do not work with older versions. The user is able to choose from 230 aircraft provided with 1.9.0, altough only a few are included in the base package. Version 1.9.1, released shortly afterwards, was a bug fix release.
Version 2.0.0 (2010)
FlightGear 2.0.0 reflects the maturation of the OpenSceneGraph port that started with the previous 1.9.0 release. In addition to many internal code improvements, FlightGear 2.0.0 marks the introduction of many new exciting improvements in the graphics and sound system, as well as improved usability of key features, and improved behavior of exsisting features. Highlights of this new version include: Dramatic new 3D clouds, dramatic lighting conditions, improved support for custom scenery, and many many new and detailed aircraft models.
Version 2.4.0 (2011)
Starting with version 2.4.0, the FlightGear team adopted a release plan. From then on, a new version is released every February and August.
See Release plan#Detailed time schedule and checklist for the main article about this subject.
Following the cancellation of 3.6, the modern FlightGear team revised the release plan and process. New releases are essentially selected and tuned "nightlies" instead of special compilations.
Also, in this release the concept of rotating default airports first started. All FlightGear releases after 2016.1 have unique default airports and 'codenames'.
See Release plan/Lessons learned#2016.1 for the main article about this subject.
Final build code release dates by year.
|July 17, 1997||First major code release|
|September 23, 1997||0.12|
|December 9, 1997||0.15|
|December 17, 1997||0.18|
|December 30, 1997||0.19 (first binaries)|
|January 6, 1998||0.22|
|Mar 11 98||0.37|
|April 8, 1998||0.41|
|April 14, 1998||0.42|
|April 23, 1998||0.43|
|Apr 28, 1998||0.44|
|May 7, 1998||0.45|
|May 11, 1998||0.46|
|May 18, 1998||0.47|
|June 9, 1998||0.48|
|June 27, 1998||0.49|
|July 13, 1998||0.50|
|July 21, 1998||0.51|
|August 15, 1998||0.52|
|September 2, 1998||0.53|
|September 25, 1998||0.54|
|October 23, 1998||0.55|
|November 23, 1998||0.56|
|January 21, 1999||0.57|
|February 10, 1999||0.58|
|March 31, 1999||0.59|
|May 26, 1999||0.6.0|
|June 21, 1999||0.6.1 (Stable)|
|September 11, 1999||0.7.0 (Development)|
|October 22, 1999||0.7.1 (Development)|
|February 17, 2000||0.7.2 (Development)|
|May 18, 2000||0.7.3 (Development)|
|July 20, 2000||0.7.4|
|September 18, 2000||0.7.5|
|December 19, 2000||0.7.6|
|June 20, 2001||0.7.7|
|July 13, 2001||0.7.8|
|February 16, 2002||0.7.9|
|April 20, 2002||0.7.10|
|September 7, 2002||0.8.0|
|December 3, 2002||0.9.0|
|December 5, 2002||0.9.1|
|June 4, 2003||0.9.2|
|October 24, 2003||0.9.3|
|March 26, 2004||0.9.4|
|July 29, 2004||0.9.5|
|October 12, 2004||0.9.6|
|January 18, 2005||0.9.8|
|November 17, 2005||0.9.9|
|April 5, 2006||0.9.10|
|December 17, 2007||1.0.0|
|December 22, 2008||1.9.0|
|January 25, 2009||1.9.1|
|February 25, 2010||2.0.0|
|August 17, 2011||2.4.0|
|February 17, 2012||2.6.0|
|August 17, 2012||2.8.0|
|February 17, 2013||2.10|
|September 21, 2013||2.12|
|February 17, 2014||3.0|
|October 15, 2014||3.2|
|February 17, 2015||3.4|
|N/A||3.6 (unreleased, see here)|
|February 17, 2016||2016.1.1 (new versioning scheme)|
|May 7, 2016||2016.1.2 (bugfix release)|
|May 17, 2016||2016.2.1|
|September 12, 2016||2016.3.1|
|November 19, 2016||2016.4.1|
|November 23, 2016||2016.4.2 (bugfix release)|
|December 5, 2016||2016.4.3 (bugfix release)|
|December 28, 2016||2016.4.4 (bugfix release)|
|February 23, 2017||2017.1.1|
|March 1, 2017||2017.1.2 (bugfix release)|
|April 4, 2017||2017.1.3 (bugfix release)|
|May 22, 2017||2017.2.1 (bugfix release)|
|September 20, 2017||2017.3.1|
|N/A||2017.4.1 (skipped due to RL)|
|N/A||2018.1.1 (due 2018 Feb 17)|
Cycled default airports
|2016.1||San Francisco (transition)|
|2016.3||Rio de Janeiro|
- Internet Archive: Wayback Machine for http://www.flightgear.org/
- Old website on December 5, 1998
- link ("A view from the ground near Tucson, AZ (KTUS)", old FlightGear screenshot)
- link ("Here's one of the Grand Canyon with a rock face texture. I know this looks funny, but I'm just experimenting here.", old FlightGear screenshot)