The country where the mother holds citizenship. Very few countries have birthright citizenship so this wouldn't be unusual. I mean the birth would be but the child sharing only its parent(s)' citizenship(s) would not be.
To address your update: if the plane happened to be parked in one of the few countries that gives birthright citizenship and its mother met whatever the specifications were (for instance in most birthright countries she at least has to have a visa) then the baby would get the citizenship of the nation in which the tarmac is situated.
I cant really gove you an answer,but what I can give you is a way to a solution, that is you have to find the anglde that you relate to or peaks your interest. A good paper is one that people get drawn into because it reaches them ln some way.As for me WW11 to me, I think of the holocaust and the effect it had on the survivors, their families and those who stood by and did nothing until it was too late.