I used to attach a Scotland flag to my cars, so that I could show my nationality when travelling away - including England. However since the Independence Referendum of 2014, that's all the Scottish flag now means - that you support independence. So I no longer feel able to put MY flag on my car.
My other flag is the United Kingdom's Union Jack, because I'm a Brit and proud to be that too. But here in the West of Scotland, the Union Jack means all sorts of things which I don't agree with, so I can't fly that flag either.
So I can't display any flag any more except, maybe, the EU flag?