We investigate the competitive effects of the merger between Delta Air Lines and Northwest Airlines (2009) in the … increases of about 11 percent on overlapping routes and about 10 percent on routes which experienced a merger-induced switch of … the operating carrier. Over a longer period, however, our analysis reveals that both merger efficiencies and post-merger …

We analyze mergers and entry in a differentiated products oligopoly model of price competition. Any merger that does … not yield efficiencies is unprofitable if it induces entry sufficient to preserve pre-merger consumer surplus. Thus … specific magnitudes of efficiencies and post-merger entry, and these combinations are identified from pre-merger market shares …