Not an English speaker here but I have a piece of paper that says I understand English so I think I understand the language of Shakespeare
So in the following text the bold part
the Union shall negotiate and conclude an agreement with that State, setting out the arrangements for its withdrawal, taking account of the framework for its future relationship with the Union
tells me that negotiations for the day after the withdraw are part of the general discussions triggered by the Article 50.
Obviously (and boy I am thankful) PPRuNe it is not a linguistics forum so let's remain on aviation. So it seems there is an abundance of countries ready to host U2 and evenutally offer nationalities to key staff - is the current CEO also the owner of the airline as to establish nationality /ownership of the airline?