Well I can only speak for European Union countries. But now you cannot be retired from a job on grounds of age.
I was to retire from my airline at 55. I still can do so. But the retirement age has been raised to 65.
This seems to be an agreed age that you are still fit and sound mind, however a legal challenge could alter this, but I'm doubtful that anyone will try. 65 is old enough, believe me!
I have known (on the old system of 55 to retire) of the airline I work for, recruiting at 48 for a 7 year career. Even though they never got to Captains level and pay, but that didnt bother the airline.
To summorise, there isnt an upper age limit. Yes, some airlines would budget the type rating into the cost of hiring, so wouldn't take on someone at 61 maybe. But some force you to pay for your type rating anyway!