@T668 - Define 'employee', I thought I had covered this. However, it depends on the contract that exists between RYR and BRK pilots, as individual contractors they are free to walk away any time, if that is their contract. If they are direct employees of RYR with security of tenure as recognised in law then it is a different matter. Please research.
It will not be 100% of employees but 100% of the bargaining unit, in this case qualifying pilots. It is the same for CC and engineers, hence why I think having separate unions is stupid but if you want to remain apart, remain apart.
I thought the link I posted pretty well covered it or haven't you looked there?
When it comes down to law v opinion, law wins.
PS According to a letter I read from a rocket scientist in that scurrilous leftie rag "The Guardian", rocket science is quite easy, stuff propelant in tube, point at sky, light it and stand back. Control is the hard bit.