Going back some thirty-odd years, I recall hearing of a very experienced Viscount skipper (those were the days) who reached the ripe old age of 55 and was promptly chopped by BA. As luck would have it, Air UK were then gearing up for expansion and said pilot found himself as a TRI on the F27 at the same base. So he landed on his feet but I don't know if there was any significant pay differential.