Bigger competitors often match prices of discount carriers like Virgin America, which had 20% of all passengers flying between JFK and LAX in the first quarter, according to consulting firm Oliver Wyman Group's PlaneStats database.

WSJ: Decoding Airline Ticket Costs

Besides the work by consulting firms cited in the text, publications on banking subjects on the websites of Mercer Oliver Wyman and Boston Consulting Group also proved useful.

ECONOMIST: Sources and acknowledgements

According to a recent study by Mercer Oliver Wyman, a consulting group, and Morgan Stanley, an investment bank, cross-border mergers can work if the buyer brings more sophisticated information-technology and risk management to the target.

ECONOMIST: European banks