Packages that travel through FedEx shipping on ground typically do not travel on Sunday and then on Monday they continue to travel.
So the weekended is not factored into the shipping time because on Sundays FedEx is closed and the trucks that deliver packages over the road from state to state are usually not working either.
Whenever I get something shipped through FedEx the tracking stops updating on Friday and then nothing is updated on Sunday and then when Monday comes around the tracking gets updated and shows that the package is traveling again.
So no packages through FedEx do not travel on Sunday throughout the system.