Singapore is not a representative example of... anything, honestly. Certainly not of "EU / Japan / Korea" which was the original question. So I have no idea what you're getting at.

I'm confused here. Were the Singapore Airlines pilots unionized? If yes, was it illegal for them to strike? These types of "strong man" posts do so little for me. Zero useful context provided and lacking in any nuance.

For example, some light Googling tells me:

    Mr Lee had in 1980 taken the pilots' union to task for staging an unofficial work-to-rule protest in November, to demand a 30 per cent basic pay...

To me, "work-to-rule protest" isn't illegal. Annoying, yes, but legal in most places. 30% increase in basic pay: Maybe their current pay was far too low? Again: No deeper info provided in your post.