What Does a No Fly Zone Mean?

In any confrontation between these two nations, it was understood at the highest level that an incursion in west berlin is a full blownnucler exchange. The only way to defend us Aircraft requires the united states to actively bombnd take out anti air systems that are stationed within the nation of russia. So now we are not just talking about a no fly zone. We are talking not even just talking about shooting russian planes that are attacking ucrane out of the sky. And now what do we have here? We have a total cluster fuck.