bugman wrote in Tue Jan 16, 2018 9:25 am:5. c) You must license the entire work, as a whole, under this License to anyone who comes into possession of a copy.
You will have a very hard task to argue in court that your aircraft is not a whole. Let me quote the Free Software Foundation licensing department:
I'll stand up in court and argue this and I suspect that the court would find in my favour (but the only true test of this is actually in court).
We've had this discussion before[1] and I don't really want to rehash it; but basically my view is that the GPL can only legally effective as a licence when the content is distributed.
If I don't distribute any of the GPL that is licenced, then the licence terms cannot be enforced in a court because there is no legal statute that applies. i.e. licence only applies when distributing (copying) protected content.
[1] https://forum.flightgear.org/viewtopic.php?f=42&t=28025&p=265064#p265062