Guys & gals, you're good at your job but hopelessly outclassed as negotiators.
We can argue about the thrust of your statement, but I simply can't be bothered. Anyway, unions such as BALPA employ full time, professional negotiators (Principle Negotiator - PN), who really do know their stuff and are probably far more experienced that most employers when it comes to bargaining.
A trade union's power of persuasion comes from it's membership density, that power is channelled through the reps, who are guided by the PN.