A friend of mine works nights driving the mail from Manchester, NH down to the GMF (general mail facility) in Boston and then on into Logan Airport.
He told me that UPS regularly delivers filled "post cons" (air freight containers that are designed to fit in airplane bellies) to the USPS to transport.
There is every chance that any given UPS shipment was at least partially handled by the USPS. Probably the same for other shippers too.
PANTERA INTERNATIONAL
A DE TOMASO CAR CLUB
Presents the De Tomaso Forums
The On-Line Meeting Place for De Tomaso Owners and Enthusiasts From Around the World
Clicking on the banner will take you to the sponsor's website.