Originally Posted by PilotAnalyst

I was curious what each Regional Code-share System looked like amongst the majors. Especially, if it was broken down by partner and aircraft, and compared with Mainline fleet size.

Regional CodeShare Profiles | Audries Aircraft Analysis
Alaska Airlines Regional Codeshare | Audries Aircraft Analysis
American Eagle Regional Codeshare | Audries Aircraft Analysis
Delta Connection Regional Codeshare | Audries Aircraft Analysis
United Express Regional Codeshare | Audries Aircraft Analysis
US Airways Regional Codeshare | Audries Aircraft Analysis

As were seeing a lot of realignment amongst Regional Carriers it is being circulated that most Mainline carriers want a diversity of only a few regional carriers, between 3-5. One carrier that does the bread and butter, and that is able to run significant lift and perks when needed (more expensive). Two Mediocre carriers that may not have much flexibility or perks but add diversity (for a reasonable cost). Finally one carrier that is extremely cheap and small, and is understandably unable to offer much quality. This final carriers purpose is to keep the other carriers in check financially.

Perks might be considered Econ Fuel Profiles, Single Engine Taxi, special airport qualifications etc. Significant lift could be considered having sufficient capacity to handle most of the seasonal swings in traffic.

The Data is from the websites database and is fairly current but as always its difficult to keep it updated up to the month, so their may be slight errors in it. Hopefully it will be of help to those trying to determine where their regional might find itself over time with respect to the future of the 50 seater, and the 3-5 regional model.

The following is not mine but it is a very good resource on past trends.
Airline affiliates and CPA's