...the only way you will sway (them) from their agenda is to get the public on side and more than likely that will only be done by playing the safety card...
The public and the media absolutely need to be on side to stop off-shoring. Managers need to be persuaded that bad publicity on this will affect ticket sales.
The
PR needs to be handled very delicately. Purely playing the safety card against foreign labour can very quickly be twisted to look like xenophobic bigotry.
Also any actual industrial action resulting in cancelled or delayed flights will only alienate the public. I'd bet folding money that in light of any industrial action, all major newspapers & media outlets will find some sob story about an orphan child who's dying of some horrid disease, who's only wish is to go on some exotic holiday. But alas they cannot because of those rich, greedy, xenophobic, pilots. (Just as media has done in the past.)