United Airlines chief executive Scott Kirby reportedly raised the prospect of a merger with American Airlines during a meeting with US President Donald Trump in late February, according to Reuters. Such a deal would combine the world's two largest carriers by international flight capacity, reducing the US aviation industry's dominant "big four" — United, American, Delta and Southwest, which already control 74% of domestic passenger capacity — to three. Critics and competition experts warn the consolidation could reduce consumer choice and drive up ticket prices, while US Transportation Secretary Sean Duffy acknowledged industry merger talk but said any deal would face close regulatory scrutiny.