Its hard to put an exact definition on that b/c YMMV. Some do a handful of international segs with lots of miles and little segs and then you got purely domestic with many segs with little miles. As previously stated FFers know the ins and outs of airlines dealing with fare rules, good seats, "getting the upgrade", knowing their options, and so forth. Many have different sets of airport club memberships with their favorite "angels". As you can see many different elements go into this catagory of a frequent flyer which I equate with more of a road warrior (or air warrior).