Thomas Cook = 5 on, 9 off = 50 % pay. Not actively encouraged due to reasons above. Perhaps only one or two out of 350 pilots actually do it.
Due to being a charter airline, and hence a quiet winter, the company encourages pilots to take the winter off to do other things. (Although they may restrict the amount of flying you do). You get 70% of your salary, all year round, and 6 months off over the winter.
Also available is half paid leave in the winter.