Only just come in on this, sorry if I repeat the obvious.
In 1958 ( age 23 ) my ExSp33db1rd contract stipulated retirement at 55 ( tho' the UK age was 60, I think ), I considered some of the Ex WW II pilots I flew with extremely old men, tho' I guess they were only late 40's - it's all relative.
I changed airline and flew to a compulsory 60, and still considered myself a young man, and was disappointed that a proposed extension to 65 hadn't taken place at that time, I didn't miss the long nights and hotel hassles but I did miss the flying.
I was often asked why I was still flying at my age, " because I'm still trying to get it right " I always replied, and on my very last 747 landing I KNOW I could have handled the cross-wind better. Now I'll never get the chance to prove it !
New Zealand has no age limit, and I think that had I already been licenced and employed there I could possibly have continued, but there was no way that a 60 yr. old Foreign Alien was going to be started, so I eventually turned to the recreational world, and I've only now had a temporary ( I hope ! ) restriction - to fly with a qualified pilot - put upon my licence.
As a Microlight (LSA) instructor one of my first 'students' was a 78 yr. old who admitted to having had a bit of previous flying experience. After 2 circuits I got out. I learned later that he had learnt to fly at age 10 ( I understand that not long after that some creative 'editing' of a Birth Cert. had occurred, but my lips are sealed ) - and never stopped until his G.A. medical started giving him issues that are not an issue for the Microlight certificate. A few years later, then over 80, he flew his bride of 60 years over their village at the precise minute, hour, and day of their Golden Wedding Anniversary, and he recently appeared in the local Press as N.Z.'s oldest pilot flying solo, as he " saluted " the commemoration of a re-sited War Memorial with a fly-past in his home town. Brings tears to the eyes, I would be satisfied to achieve even half of that.
I know the subject is commercial flying, but if one is capable, both professionally and medically, who has the right to stop us - other than the bureaucrats and doomsayers ?