There's no real indication that brexit is going to affect the employment trend at BA at this point. The recruitment being done today is (as far as I'm aware) based on planned retirements, running the current schedule and the additional long haul hulls, not by expansion driven by the wonderful UK economic performance. If I'm wrong though, maybe those with the self entitlement to apply purely for long haul positions and therefore not taking one of the many available positions on short haul will regret their decision not to be able to join the company at the earliest opportunity.