Many years ago, when the B707 fleet at SQ was the most in numbers, I was approached by a local Captain and asked how to contact ALPA in the USA, as they wanted to form a pilots union.
I passed along the contact telephone numbers, AFTN, SITA and telex details and then mentioned....Albert, you are waisting your time.
The
management decides what the roster/pay/leave, days off (etc) will be, and no 'union' will dictate to the airline management.
And managements decisions will be backed up by the respective government minister, make no mistake.
Think of Singapore as similar to HKG...with a happy face painted on, and perhaps a bit of cleaner air.