I have a block of 4 and a block of 3 days off next month. I had to trade a day to get the block of 3 off. Everything else is single days off. I've seen another captain's schedule that also has a block of 4 and a block of 3 off. I've seen another schedule that has the first 7 days off, then the rest of the month is single days off.
There is available open time, and while I've been able to trade a bit to make my schedule more to my liking, I've also been shot down for trades because they've designated certain days "100% Fly Days" and they're not allowed to permit crewmembers to trade out of, PTO or drop those days.