Rumor has it that United Airlines (UAL.US) and Delta Air Lines (DAL.US) last year's merger plan to build a “superairline” for the century finally ran aground due to antitrust

The Zhitong Finance App learned that according to media reports quoting people familiar with the matter on July 26, United Airlines (UAL.US) CEO Scott Kirby personally called Delta Air Lines (DAL.US) CEO Ed Bastian in 2025 to discuss the possibility of a merger between the two companies. If this idea comes true, it will create the world's largest airline with a market capitalization of close to 100 billion US dollars and control about 50% of the American air travel market. However, after carrying out initial due diligence, Delta management decided not to proceed, and the two sides did not enter into formal negotiations.

The 10-billion dollar merger plan: a strong alliance of profit “oligopolies”

United Airlines and Delta are the second and third largest airlines in the US, respectively, and together contributed more than 90% of the profits of the American airline industry in 2025. Based on the market value at the time, the valuation of Delta Air Lines was about 56 billion US dollars, United Airlines was about 38 billion US dollars, and the combined entity size was close to 100 billion US dollars. The combined revenue of the two companies in 2024 is approximately US$120 billion.

For United Airlines, Delta's appeal isn't just about size—Delta has long been regarded as the industry's benchmark for profitability, high-end customer experience, and operational reliability. Kirby has publicly praised Delta's strategy of focusing on attracting high-profit travelers rather than price competition. This concept has also profoundly influenced United's transformation direction in recent years. The merger will provide United with access to Delta's profitable markets in New York and Boston, as well as resources from its transatlantic joint venture partners, including Air France-KLM and Virgin Atlantic.

Anti-monopoly “Iron Curtain”: Why the deal is bound to fail to advance

However, anyone familiar with the regulatory environment of the US aviation industry can foresee the outcome of this deal. Over the past 20 years, American Airlines has consolidated from 10 major airlines to 4 — United Airlines, Delta Air Lines, American Airlines, and Southwest Airlines, which together control about 80% of the domestic market share. The Ministry of Justice is increasingly cautious about further integration of major airlines.

People familiar with the matter pointed out that if United Airlines and Delta Air Lines merged, it would trigger the toughest antitrust scrutiny since the Department of Justice successfully blocked JetBlue's acquisition of Spirit Airlines. Regulatory hurdles include the possibility that crowded airports such as Newark Liberty International Airport and LaGuardia will be forced to sell flight slots. Any formal merger proposal requires approval from the Ministry of Justice's antitrust department and the Ministry of Transportation, a process that can take 12 to 18 months.

It was these almost insurmountable regulatory hurdles that caused both parties to decide that the deal was “unrealistic”, and initial discussions never entered the formal negotiation stage of price or structure.

M&A ambitions unabated: From Delta to American Airlines' “double track trial”

The Delta Air Lines contact that came to light this time revealed Kirby's more ambitious industry integration ambitions. Reports show that after getting in touch with Delta, Kirby also made a separate proposal to US President Trump to merge United Airlines with American Airlines (AAL.US). However, American Airlines CEO Robert Isom directly rejected the proposal and criticized it as “anti-competitive.”

This “two-track trial” shows that despite facing huge regulatory resistance, United Airlines management is still actively evaluating the possibility of reshaping the competitive landscape through large-scale mergers and acquisitions. US Secretary of Transportation Sean Duffy said in April this year that the US aviation industry “still has room for merger,” implying that the regulatory environment may be more relaxed than the previous administration. However, antitrust experts pointed out that even if the regulatory attitude tends to be relaxed, it is unlikely that the merger between the two major US airlines will be approved.

Industry Implications: The will to integrate is still there, but the regulatory ceiling is clear

After successive rejections from American Airlines and American Airlines, Kirby publicly stated in June that United Airlines would not pursue industry integration in the foreseeable future. He confessed to the media at the IATA annual meeting: “I don't think integration is likely for United Airlines. That doesn't mean we won't continue to buy assets in the market, but the probability of consolidation is low.”

However, the Delta Air Lines contacts revealed this time that the American airline industry's will to integrate still exists. The four major airlines dominate the pattern of about 80% of the domestic market, leaving the main hubs extremely limited room for growth through organic expansion. Smaller operators such as JetBlue and Alaska Airlines are seeking growth through acquisitions and partnerships.

For investors, the report highlights the continued interest of major US airlines in consolidation, despite regulatory hurdles making large-scale mergers and acquisitions increasingly difficult. Any merger between United Airlines and Delta will face severe antitrust scrutiny, but the underlying drivers of industry consolidation — scale effects, hub control, and cost synergy — have not disappeared. Similar bold ideas are likely to make a comeback when the regulatory environment is likely to change marginally.