If you remove unions from all airlines, then it's very likely going to bring the salaries up for inexperienced pilots, because then the airlines have more flexibility as to how much they pay pilots per head, and will likely compete just like they do on the marketplace in other categories of jobs.
No examples of a union being "busted" but in a few cities there's been a pattern of massively increased junior salaries for teachers, together with a significant weakening of teachers' union power.
Having seen what some new pilots make and the shit routes they get all this talk about how negotiations somehow favor them over senior pilots is odd, those negotiations are refinements of existing contracts which have always benefited those with the most years. They encourage staying at your airline because when you don't you fall in rank and pay, the same when you get bought out. Hence when mergers occur the different unions have to agree to their members don't lose out.
In a highly specialized and professional trade as pilots are I am still trying to see why a union is necessary.
Well when a union is busted usually all of the union members are let go. The smaller number of people that do get jobs at the same place usually get just as good or better offers, especially if they are newer.
It's not across the board because of the top union earners that are privileged with triple salary for simply being in a place longer than the others. Their salaries will get slashed. That's always going to happen when you convert from a system that rewards people based on time served rather than merit.