Back in 2001 while working at the Fed Ex hub in Memphis: the USPS started sending a lot of its mail via Fed Ex. Big yellow bags with a plastic container full of envelopes in each bag would come through the sort. Apparently the USPS had/has a multi-million dollar/ multi-year deal with Fed Ex to ship their mail across the country.
Can anyone verify this?
Yup.. cheaper to fly it fedex than truck it or use their own planes (if USPS even has them any more)