Southwest’s merger with Muse was threatened.

The Justice Department said the Transportation Department should consider arguments that might be raised in opposition to a proposed merger of Muse Air and Southwest Airlines. But in a position paper made public, the department’s antitrust division also said it did not believe that formal public hearings were required. Muse and Southwest have asked the government to exempt their proposed merger from the public hearing requirement of the Federal Aviation Act. In papers filed with the Transportation Department, the antitrust division said it opposes any blanket waiver of public comment opportunities.