I knew a couple of pilots for an American airline co. At that time, the larger airlines would have pilots fly 3 flights over ~3 days (if in the US, 3 days; international flights would screw with this). Then they'd get a day or so off, then fly again; at the tightest, you'd have 3 days of flying, one day off, then repeat.
As one of them explained, this schedule meant that, if you too every 4th day off, you could get a whole month of vacation by taking 7-8 days, spaced in that fashion.
For the more local/regional airlines, I think you flew more hours, but I don't know how they scheduled you. By local/regional, I mean, e.g., Republic Airlines--which used to operate here in the Midwest; one of these pilots flew for it before it merged with Northwest--where they would do closed loop routes such as
Lansing, MI
-> Grand Rapids, MI or Traverse City, MI
-> Green Bay, WI
-> Chicago/Midway, IL
-> Jackson, MI
-> Detroit, MI
-> start (Lansing, MI)
