Flights arrive several times per day.
If you are by yourself, this might be cheaper than a taxi. They meet every flight and their bus will hold 12 people. If you take the Hope-Princeton route it is very pretty, though a bit slower and much twistier than the Coquihalla. I prefer the Hope-Princeton myself as there are more places to stop for coffee and gas. There is bus service to Penticton via Greyhound from most places in BC if you are so inclined.