Unless it's a large and busy station, my hunch is they arrive at the out station Saturday a.m. and don't depart again until Monday evening. In some cases they may arrive Friday a.m. and sit until Monday evening.
Busier stations operate select flights even on Saturdays and Sundays.
For example: We have one FedEx A310 that sits on the ramp here in GRR
from Friday a.m. until Monday evening.
Our second FedEx A310 sits only from Sunday afternoon until Monday evening.
Direct KNOBS, maintain 2700' until established on the localizer, cleared ILS runway 26 left approach.