Delta originally had small ownership stakes in ASA, Comair, and Skywest. They over time, increased their stakes in EV and OH to prevent them from signing agreements with other airlines. Their stake in Skywest has lessened because they are slowly but surely rethinking their Delta Connection operations out West. ASA and Comair are based out of major Delta operations, CVG and MCO for Comair, ATL and DFW for ASA. With Comair being replaced in Florida by Chautauqua, look to see some Comair ops increase @ DFW and perhaps even starting flights@ SLC. The regional airlines were bought up in order to protect airlines. Why else is Piedmont, PSA, and Allegheny wholly owned regionals of U.S. Airways? And the same for American Eagle? One of the reasons why ASA was purchased by Delta was that in the mid-90s, Valujet was rumored to be interested in buying them (VJ co-founder Robert Priddy was one of the founders of ASA), and Delta was involved in a heated war against them.