American Airlines shares fell 3% in premarket trading Monday after the carrier dismissed the possibility of a merger with United Airlines. The stock decline came as speculation about a potential combination between the two major U.S. carriers circulated in the market.

Despite American's rejection of merger discussions, a bipartisan group of senators has requested information from both airlines about how such a consolidation could impact airline routes and passenger fares. The lawmakers are seeking details on the potential effects of any merger between the carriers on competition and pricing.

The senators' inquiry reflects ongoing concerns about consolidation in the airline industry and its impact on consumers. Previous airline mergers have faced scrutiny from regulators and lawmakers over potential effects on market competition and ticket prices.

American Airlines and United Airlines are among the largest carriers in the United States, and any merger between them would create significant changes in the domestic aviation market. The companies have not provided detailed responses to the senators' requests for information about potential merger impacts.

The discussion comes amid broader industry challenges including fluctuating demand, operational disruptions, and competitive pressures in the post-pandemic aviation environment.