I know that the big rental companies refuse to rent to drivers under age 25, but that's a different problem. I never heard of a maximum age, but it wouldn't surprise me.

Interestingly, the FAA has a hard and fast rule -- NEVER waived -- that prohibits pilots from flying commercial aircraft after they reach age 60. It doesn't matter at all if the person is in excellent physical condition; all that matters is the chronological age. This rule was upheld by the Supreme Court not too long ago.

Bruce