If a regional is wholly owned, then it doesn't really matter what the arrangement is between the regional and the major. Whether the dollars are credited to the regional or credited to the major, in the end it's all coming out of the same pocket. So for instance, saying that ASA and Comair are making a profit while Delta is making a loss isn't that meaningful, because in the end it's just an accounting arrangement. Delta could choose to impose a different arrangement on ASA and Comair tomorrow and suddenly they'd be making a loss.
Independent regional jet operators in the US get a fee per departure, fee per block hour, or some mixture/variation on this concept. Most also are compensated for major risks. So, for instance, if gas prices go up beyond what is assumed in the contract, the major compensates the regional accordingly.
Profits that most independents make are "real" in the sense that most of contracts between an independent regional and a major are negotiated at arm's length and so are determined in the marketplace. Less "real" are the profits that result from contracts that are a holdover from when the regional was wholly-owned---i.e. ExpressJet and Pinnacle. We'll have to wait until the first time these contracts are renegotiated at arm's length to see how real are the associated profits.