There isn't any agreement in place yet, so nothing is certain. This may be the case, but it isn't confirmed yet.
Exactly.
People (including politicians) can pontificate all day long about the where's and wherefore's of brexit (or BREXIT, if you need to yell) but if Joe Public decides to give flying a miss for a couple of months until it all blows over, that's just an unfortunate consequence for the aviation industry that is outside everybody's' control.
Not enough bums on seats = cashflow problems for the weak and lame = market consolidation.
Of course there will be other factors, its low cost aviation!!!
To some degree though (I don't think anybody knows how much) brexit is just an added kick in the nuts.
And, (how many times have I had to post this!)...I could not care less about brexit and how it plays out, so please don't yell "project fear" at me.