President Trump rejected the idea of a United Airlines and American Airlines merger, telling CNBC that combining the two major carriers could make them complacent. His comments came as Washington lawmakers have already expressed skepticism about the potential megadeal. Trump drew parallels to aerospace industry consolidation, arguing that fewer players lead to reduced competition and innovation.

Both airlines are currently performing well financially, according to Trump. The president's opposition adds significant political headwinds to any potential merger discussions. American Airlines shares dropped 1% in morning trading, while United Airlines shares rose 1.5%, suggesting investors interpreted the comments as reducing the likelihood of a deal.

Trump's stance represents a notable intervention in the airline industry, where consolidation has been a trend for years. His comparison to the defense sector, where he claims fewer companies have led to reduced competitiveness, provides insight into his thinking on market concentration. The president's comments effectively end speculation about a United-American merger for now, as his opposition carries substantial weight with regulators and investors.