"You gotta have a gimmick." That advice from the famous showstopping scene in the musical Gypsy was meant for strippers, but it applies to airlines as well. These days, to succeed, a small airline needs a distinct niche. It's the old "find a need and fill it" rule, and "need" typically means a service that the giant lines are not providing. Here are eight North American airlines that seem to have each found their niche.
(Seat measurements were found on SeatGuru.)