A merger between United and American airlines could reshape O’Hare International Airport and make flying more expensive and unpleasant for Chicagoans, according to aviation and antitrust experts. The potential merger, which would create the largest airline in the world, could impact O'Hare, where the two airlines together control about 80% of the airport's gates. It is unclear if any formal merger proposal process is underway and any merger involving the two massive airlines would face an uphill battle with federal regulators. A merger could result in increased competition and higher prices for consumers, particularly in relation to quality of service offered by airlines. Consumer advocates are typically skeptical of corporate consolidation, fearing reduced competition leading to higher prices and fewer options for consumers. The merger could also result in fewer discount fares and less competitive options for flyers.