United Airlines CEO Explored Mergers With Delta and American Airlines, Both Declined

Scott Kirby, chief executive of United Airlines, initiated discussions about potential mergers with two of the largest U.S. carriers: Delta Air Lines and American Airlines. Early in 2025, Kirby approached Delta, including speaking directly to its CEO, Ed Bastian, and Delta conducted preliminary due diligence on the merger idea before deciding against pursuing it. Months later, Kirby brought a similar proposal to American Airlines, seeking to merge and form a dominant airline in the U.S. domestic market.

The prospect of consolidation between any two of the 'US3'—United, Delta, and American Airlines—has historically been considered unrealistic due to antitrust concerns and the high market share these airlines command. Together, they hold approximately 52% of the U.S. domestic market. Kirby's efforts to broker combinations within these top-three carriers highlight a strategic attempt to capture over a third of this market through integration.

Kirby's approach toward these mergers marks a departure from traditional acquisition strategies focused on smaller carriers. Despite speculation, United previously ruled out piecemeal acquisitions of smaller airlines, including a public rejection of buying JetBlue, mainly due to concerns related to JetBlue's debt. Instead, Kirby has advocated for large-scale combinations to create the 'very best' airline globally, reflecting ambitious goals to reposition United at the forefront of the industry.

While Delta showed willingness to explore the idea with due diligence, it eventually chose to dismiss the merger. Conversely, American Airlines declined to engage in merger talks altogether, rejecting United's proposal both privately and publicly through stock market filings. This contrast in responses reveals differing strategic priorities among the top U.S. carriers and possibly reflects deep reservations about the competitive and regulatory implications of such mergers.

The timing of Kirby's overtures is notable against the backdrop of U.S. regulatory attitudes, particularly under the Biden administration, which has taken a tough stance on airline consolidation, as seen in blocking the JetBlue-Spirit Airlines merger. However, there is a perception that the current administration might be more receptive to mergers between major carriers, although former President Trump himself expressed opposition to a United-American merge potentially influencing the decision landscape.

Delta's market capitalization stands at about $48.18 billion, while United's is approximately $39.32 billion. This disparity indicates United would be the smaller party in any merger with Delta, complicating the potential partnership dynamics. Observers consider how leadership roles might be determined, especially with Kirby's ambitions possibly including remaining as chief executive of a merged entity, which would sideline counterpart executives such as Delta's Ed Bastian.

Kirby's expansive consolidation vision, while not embraced by Delta or American Airlines, underscores the growing pressures within the airline industry, including escalating fuel costs and competitive challenges. Smaller carriers face increasing difficulties, often leading to survival-driven mergers or acquisitions. Kirby’s strategy seeks to preemptively create a stronger competitive position by combining with another industry heavyweight, pushing beyond incremental growth via smaller acquisitions.

Despite the setbacks in garnering acceptance from his largest rivals, Kirby's outreach reflects a significant strategic intent to reshape the U.S. airline industry. His repeated attempts to pursue fundamentally transformative mergers reveal the scale of ambition driving United Airlines' leadership, even if regulatory and market realities constrain actual merger execution.

The failure of these merger talks with both Delta and American Airlines leaves United Airlines to continue navigating a competitive market structure dominated by the US3 without direct consolidation. Kirby’s efforts, nevertheless, signal ongoing merger interest at the highest levels and suggest that future shifts in regulatory or economic conditions could revive interest in large-scale airline mergers.