American Airlines CEO Robert Isom dismissed the prospect of a merger with United Airlines as anti-competitive, emphasizing instead a strategy centered on partnerships and organic growth.

Speaking during the company’s first-quarter earnings call, Isom underscored American’s (Nasdaq: AAL) commitment to maintaining its hub at Chicago’s O’Hare International Airport despite increased regulatory constraints, including recent flight caps imposed by the Federal Aviation Administration, Reuters reported. The news comes days after United (Nasdaq: UAL)’s CEO downplayed speculation about the merger. He noted that easing congestion restrictions could allow American to restore operations to roughly 500 daily departures, reinforcing its competitive positioning against United at the airport.

On the strategic front, American Airlines is evaluating opportunities to expand its partnership with Alaska Airlines, building on an existing commercial alliance that includes codesharing and loyalty program reciprocity.