The Israeli weekend surprises many tourists. It starts on Friday afternoon and ends on Saturday evening after sunset. Sunday is an ordinary working day.
There are no buses and trains during the weekend, only private taxis (which are expensive) and a limited mini-van service (called Sheroot).
It's best not to book flights into or out of Israel during the weekend, because the train service doesn't work from Friday early in the afternoon until Saturday night. The only alternative is a taxi, which is about 10 times more expensive than the train.