My father, who is retired, told me that, from his own experience, it's very difficult to get promoted once you hit age 40.
http://www.nypost.com/p/news/business/jobs/go_to_greg_hT9jn6JPPG7nuIk6T0LxnI?
http://www.nypost.com/p/news/business/jobs/go_to_greg_hT9jn6JPPG7nuIk6T0LxnI?