Your views will alter with time Jambone. There really is no issue of 'they're taking our jobs' here. The best candidates get the gig, end of story. If a UK national speaks German/French then nothing stops them from applying to Lufthansa/Air France. It works both ways. Aviation is international, you need to be thinking on a global stage and not be insular.
The likelihood is that any foreign national who starts flying for BA is going to be living in the UK and contributing to the economy with their disposable income, paying UK taxes etc. so your point about 'helping our own economy' is moot.