Update July 16, 2014
The once-independent "regional airline" industry has almost totally transitioned into the business of leasing lift to major airline brands. SkyWest leases aircraft and crews to five major carrier brands, for example. The passengers and fare revenues are those of the major carrier.
In computing and considering operational performance metrics, the situation is essentially the same as the relationship that United or American or Delta have with companies that directly lease them aircraft. The main difference is that small lift providers include crews. That much said, these entities are now critical parts of major airline operations. For example, over 50% of American-branded departures are now outsourced to these companies. The figure for United is over 60%
These are businesses that fly airliners. Therefore the relative performance in this sector is of value. In this section, AirlineFinacials.com™ compares contract flying for each of the major airlines.