United Airlines Pitched Merger with Delta Amid Antitrust Hurdles

UAL chief executive Scott Kirby approached DAL counterpart Ed Bastian in 2025 about combining the two carriers, a deal that would have created by far the largest airline in the United States, according to reports published this week. Delta ran preliminary due diligence, but the talks went nowhere and were never formalised.

The arithmetic explains why. Delta carried about 17.8% of the domestic market and United about 16.8% in the twelve months through April 2026, so a combination would have controlled roughly 34.6% of US domestic traffic, close to one passenger in three. Aviation executives have long treated a United-Delta tie-up as effectively unattainable for exactly that reason, with overlapping networks, duplicated hubs and entangled loyalty programmes compounding an antitrust problem that would have been difficult to remedy through divestitures alone.

The disclosure also reframes United's subsequent approach to American Airlines, which drew political and regulatory backlash. Read together, the two episodes show a carrier that has repeatedly tested whether consolidation of the largest US airlines is achievable, and has repeatedly found that it is not. Industry M&A has since stalled.

For shareholders the practical implication is that scale gains at the top of the US market are more likely to come from organic capacity, alliance depth and fleet decisions than from transformational mergers. Investors watching the sector may want to focus on whether United redirects the strategic energy behind these approaches into partnerships and network investment, and on how regulators respond to any further consolidation attempts among smaller carriers.

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