To your question about the US, to the best of my knowledge the major US carriers simply do not have non-union pilots. I could be wrong on that but do not know of a non-union pilot at AA, DL, CO or UA. My brother is a pilot at DL and I know they are 100% union members. It is a very different culture than here in the fragrant harbour. Of course, every friend I have in US aviation works for a currently or at one time very recently bankrupt company. Might be why I don't complain about CX management quite as much as some. My paycheck has shown up every single month for 18 years now.
The reason why it is 100% union membership is because in the U.S., the pilot unions are 'closed shop'. There's isn't the choice like you have at CX.