How long can Ferrets be in the car ?

mine have been in a car for 2 hours before and they were fine.. they could go a long amount of time if they have food and water and such.. they just fall asleep.. when i brought my first ferret she came up on a train and the train ride went for a bit over 2 hours.. they may stress a little at first but make them feel comfy.. with blankets and toys and stuff in the carrier and they will just go to sleep.. :)