Airlines love unions. They're easily fooled (see pensions, scope, SJS) plus it takes years for unions to be able to strike thanks to the RLA. Because apparently we are too important to the economy to be able to fight for the wages we deserve. Airlines can stall for years after a contract expires, while they fool the mediators with the false pretense of "good faith negotiating".
Fortunately there are so many jobs these days that people can fight with their feet. Although I still can't understand how airlines like Mesa and Gojet are still filling classes in today's market.