The problem with age discrimination, particularly in this industry - and speaking as one who has concerns about their own employment prospects when I finish training - is that no airline worth it's salt is going to send you a "thanks, but no thanks" letter that says "....because you're too old". There is a myriad of other excuses out there that would be perfectly reasonable reasons to hire a younger candidate such as they performed better on the sim check, they fit our personality profile better etc etc.
The secondary part to this, is that this is SUCH a small industry that if A.Person was start a legal challenge on the basis of age discrimination, it would effectively put paid to any chance of a job elsewhere. So a challenge is only likely to come either when someone gives up entirely (in which case the defence will merely "prove" you weren't good enough and it's just sour grapes) or when someone has secured a job with another airline, but in this case, why would you bother?
All the older candidates out there can hope is that more and more recruiters make their hiring decisions based on best for the job and that subsequent to that, we oldies can prove ourselves at least competitive with the younger.