Code is under the LGPL v2.1, as I think this is what the Helicopters mod is licensed under... Please correct me if I am wrong!
According to https://github.com/SokolovPavel/helicopter
it's actually under GPLv2 or later. (in fact, it used to be GPLv2 only, but changed to allow later versions of the GPL recently).
According to https://github.com/SokolovPavel/helicopter
it's actually under GPLv2 or later. (in fact, it used to be GPLv2 only, but changed to allow later versions of the GPL recently).