I've said it before, and I'll say it again.
Proper careers are protected by industry regulators and unions/lobby groups who help to hammer out those regulations. Proper careers guarantee those with experience; the most to lose and the least to gain from unemployment, the right to further employability. The recruitment/employment preferences of our airlines has led to a system where one's experience doing the job works directly against one's employability.
This is what you would expect a union to address.