It's a very good question.
I can't see that Brexit would do the British aviation industry any good. Two main reasons for this: 1) The CEOs of every British (and one Irish
) airline have come out in favour of remain. 2) Aviation generally benefits from the free movement of people and goods across borders. In order to continue growing (and thus continue recruiting), aviation relies on the continued free movement of people and goods. If Brexit happens and Boris and co. are successful in reducing the number of people coming to (and, whether you like it or not, going from) Britain, it's hard to see how airlines can continue to expand (and thus recruit).
You can probably see where my vote has gone, therefore