State "right to work" laws are irrelevant here. Airlines are subject to the Railway Labor Act. Generally states have very little power to regulate airlines.
Thanks for letting me know the airline labor regulations are covered by the Railway Labor Act and not the regular labor laws in the individual states that is interesting to know. So I guess I should have said that no matter which state they live in they don't have a choice but to pay their dues or quit/be fired since the Union contracts say that the airlines must fire anyone who does not pay union dues.