Trump has said too much this time (again) but I doubt that he seriously means to cancel US membership of NATO - I don't think he can do that anyway - as far as I understand it, the US National Defense Authorization Act stops any President from unilaterally taking the USA out of NATO without significant Senate and House approval. Similarly, I do not believe that he is seriously advocating any Russian attack on any part of Europe.
If the European NATO members wanted rid of US influence then I suppose they could form their own alliance but a NATO without the USA would not be much of a deterrent at all. Why you mention NORAD is a mystery, it is nothing to do with NATO and it looks like that you are just speculating.
Like Trump, maybe you should slow down a bit.