Spent close to 12 years at FedEx and unlike past career spots, I was unable to advance beyond an individual contributor, some of that may be me, but I believe most was that management positions were few and far between, unless you were working out of Memphis, the primary location. Had many different 'jobs' but all were lateral.
Otherwise it is a company that truly believes in a balanced work-life and is listening to employees. They really do believe in TQM (or known as QDM internally) as well as taking personal responsibility for your actions. You tend to agree that their internal mantra of LPSP (Living PSP - People Service Profit) is a supported up and down the management chain.
Lack of upward opportunities.