Changing the FlightGear license

The subject of changing the FlightGear license to a non-commercial one comes up on a regular basis on the -devel list, typically with a wish to stop the use of FlightGear by FlightProSim etc.

This page sets out the main reasons why the core FlightGear developers do not intend to change the license, based on the views of long-time contributors to the source code expressed on the list. While individual contributors may disagree on particular points, it represents the overall view of the core contributors.

Those wishing to propose a license change are encouraged to read this instead of posting to the -devel list.

• Philosophically. The freedom to use FlightGear commercially is a key freedom provided by the GPL. Removing that freedom makes FlightGear less free, and would discourage contribution from current developers who particularly value freedom.
• Commercial Contribution/Use. Some contributions are the direct result of commercial use of FlightGear, and some current contributors are paid for their FlightGear work, directly or indirectly. Moving to a non-commercial license would immediately impact these contributions.
• Distribution. FlightGear is packaged in a number of Linux distributions. Changing to a less free license would stop it from being distributed in this way and reduce its reach.
• Practicality. Changing the license would require agreement from everyone who has ever contributed to FlightGear. Given the age of the project (15 years) and huge number of contributors (some of whom have sadly passed away), this isn't practical.
• Effectiveness. Re-distributors/forkers such as FlightProSim have so far shown no interest in keeping up with the latest FlightGear version, and any license change would not impact their use of back-level software. It is therefore unlikely that any license change would have an impact.